P2x7 modulators

ABSTRACT

The present invention is directed to compounds of Formula (I), which includes enantiomer and diasteromers thereof: These compounds are suitable for use in the treatment of diseases associated with P2X7 receptor activity such as diseases of the autoimmune and inflammatory system, diseases of the nervous and neuro-immune system, diseases involved with neuroinflammation of the Central Nervous System (CNS) or diseases of the cardiovascular, metabolic, gastrointestinal and urogenital systems.

FIELD OF THE INVENTION

The present invention is related to compounds having P2X7 modulatingproperties, pharmaceutical compositions comprising these compounds,chemical processes for preparing these compounds and their use in thetreatment of diseases associated with P2X7 receptor activity in animals,in particular humans.

BACKGROUND OF THE INVENTION

The P2X7 receptor is a ligand-gated ion channel and is present on avariety of cell types, largely those known to be involved in theinflammatory and/or immune process, specifically, macrophages andmonocytes in the periphery and predominantly in glial cells (microgliaand astrocytes) of the CNS. (Duan and Neary, Glia 2006, 54, 738-746;Skaper et al., FASEB J 2009, 24, 337-345; Surprenant and North, Annu.Rev. Physiol. 2009, 71, 333-359). Activation of the P2X7 receptor byextracellular nucleotides, in particular adenosine triphosphate, leadsto the release of proinflammatory cytokines IL-1β and IL-18 (Muller, et.Al. Am. J. Respir. Cell Mol. Biol. 2011, 44, 456-464), giant cellformation (macrophages/microglial cells), degranulation (mast cells) andL-selectin shedding (lymphocytes) (Ferrari et al., J. Immunol. 2006,176, 3877-3883; Surprenant and North, Annu. Rev. Physiol. 2009, 71,333-359). P2X7 receptors are also located on antigen-presenting cells(keratinocytes, salivary acinar cells (parotid cells)), hepatocytes,erythrocytes, erythroleukaemic cells, monocytes, fibroblasts, bonemarrow cells, neurones, and renal mesangial cells.

The importance of P2X7 in the nervous system arises primarily fromexperiments using P2X7 knockout mice. These mice demonstrate the role ofP2X7 in the development and maintenance of pain, as these mice areprotected from the development of both adjuvant-induced inflammatorypain and partial nerve ligation-induced neuropathic pain (Chessell etal., Pain 2005, 114, 386-396). In addition, P2X7 knockout mice alsoexhibit an anti-depressant phenotype based on reduced immobility inforced swim and tail suspension tests (Basso et al., Behav. Brain Res.2009, 198, 83-90.). Moreover, the P2X7 pathway is linked to the releaseof the pro-inflammatory cytokine, IL-1β, which has been linked toprecipitation of mood disorders in humans (Dantzer, Immunol. AllergyClin. North Am. 2009, 29, 247-264; Capuron and Miller, Pharmacol. Ther.2011, 130, 226-238). In addition, in murine models of Alzheimer'sdisease, P2X7 was upregulated around amyloid plaques indicating a roleof this target in such pathology as well (Parvathenani et al., J. Biol.Chem. 2003, 278, 13309-13317).

Several reviews on small molecule inhibitors of P2X7 which have beenpublished are: Guile, S. D., et al., J. Med. Chem, 2009, 52, 3123-3141;Gunosewoyo, H. and Kassiou, M., Exp Opin, 2010, 20, 625-646.

In view of the clinical importance of P2X7, the identification ofcompounds that modulate P2X7 receptor function represents an attractiveavenue into the development of new therapeutic agents. Such compoundsare provided herein.

SUMMARY OF THE INVENTION

The invention is directed to the general and preferred embodimentsdefined, respectively, by the independent and dependent claims appendedhereto, which are incorporated by reference herein. One aspect of thisinvention concerns compounds of Formula (I):

-   and enantiomers or diastereomers thereof;-   and pharmaceutically acceptable salts thereof;-   wherein:-   R^(a) is

-   -   R¹ is halo or C₁-C₃alkyl;    -   R² is independently selected from the group consisting of: H,        halo, and C₁-C₃perhaloalkyl;    -   R³ is H or halo;    -   R⁴ is halo,    -   R⁵ is halo or C₁-C₃perhaloalkyl;

-   R^(b) is independently selected from the group consisting of:

-   -   Wherein:        -   R⁶, R⁹, R¹⁰, R¹², R¹⁴ are independently H or halo;        -   R⁷, R⁸, R¹³ is independently selected from the group            consisting of: H, halo and OC₁-C₃alkyl;        -   R¹¹ is independently selected from the group consisting of:            H, halo and C₁-C₃perhaloalkyl;

-   R^(c) is selected from the group consisting of:

-   R^(d) and R^(e) are independently H or C₁-C₃alkyl; and-   provided that at least one of R^(c), R^(d) and R^(e) are not H.

Further embodiments are provided by pharmaceutically acceptable salts ofcompounds of Formulas (I), pharmaceutically acceptable prodrugs ofcompounds of Formula (I), and pharmaceutically active metabolites ofcompounds of Formula (I).

In certain embodiments, the compounds of Formula (I) are compoundsselected from those species described or exemplified in the detaileddescription below.

In a further aspect, the invention relates to enantiomers anddiastereomers of the compounds of Formula I, as well as thepharmaceutically acceptable salts.

In a further aspect, the invention relates to pharmaceuticalcompositions for treating a disease, disorder, or medical conditionmediated by P2X7 receptor activity, comprising an effective amount of atleast one compound selected from compounds of Formula (I),pharmaceutically acceptable salts of compounds of Formula (I),pharmaceutically acceptable prodrugs of compounds of Formula (I), andpharmaceutically active metabolites of Formula (I).

Pharmaceutical compositions according to the invention may furthercomprise one or more pharmaceutically acceptable excipients.

In another aspect, the chemical embodiments of the present invention areuseful as P2X7 receptor modulators. Thus, the invention is directed to amethod for modulating P2X7 receptor activity, including when suchreceptor is in a subject, comprising exposing P2X7 receptor to aneffective amount of at least one compound selected from compounds ofFormula (I), pharmaceutically acceptable salts of compounds of Formula(I), pharmaceutically acceptable prodrugs of compounds of Formula (I),and pharmaceutically active metabolites of compounds of Formula (I).

In another aspect, the invention is directed to a method of treating asubject suffering from, or diagnosed with a disease, disorder, ormedical condition mediated by P2X7 receptor activity, comprisingadministering to the subject in need of such treatment an effectiveamount of at least one compound selected from compounds of Formula (I),pharmaceutically acceptable salts of compounds of Formula (I),pharmaceutically acceptable prodrugs of compounds of Formula (I), andpharmaceutically active metabolites of compounds of Formula (I).Additional embodiments of methods of treatment are set forth in thedetailed description.

In another aspect, the method of studying isotopically labeled compoundsin metabolic studies (preferably with ¹⁴C), reaction kinetic studies(with, for example ²H or ³H), detection or imaging techniques [such aspositron emission tomography (PET) or single-photon emission computedtomography (SPECT)] including drug or substrate tissue distributionassays, or in radioactive treatment of patients. For example, an ¹⁸F or¹¹C labeled compound may be particularly preferred for PET or SPECTstudies.

An object of the present invention is to overcome or ameliorate at leastone of the disadvantages of the conventional methodologies and/or priorart, or to provide a useful alternative thereto.

Additional embodiments, features, and advantages of the invention willbe apparent from the following detailed description and through practiceof the invention.

Additional embodiments of this invention include methods of makingcompounds of Formula (I), pharmaceutically acceptable salts of compoundsof Formula (I), pharmaceutically acceptable prodrugs of compounds ofFormula (I), and pharmaceutically active metabolites of Formula (I).

DETAILED DESCRIPTION OF THE INVENTION

A compound of Formula (I):

-   and enantiomers or diastereomers thereof;-   and pharmaceutically acceptable salts thereof;-   wherein:-   R^(a) is

-   -   R¹ is halo or C₁-C₃alkyl;    -   R² is independently selected from the group consisting of: H,        halo, and C₁-C₃perhaloalkyl;    -   R³ is H or halo;    -   R⁴ is halo,    -   R⁵ is halo or C₁-C₃perhaloalkyl;

-   R^(b) is independently selected from the group consisting of:

-   -   Wherein:        -   R⁶, R⁹, R¹⁰, R¹², R¹⁴ are independently H or halo;        -   R⁷, R⁸, R¹³ is independently selected from the group            consisting of: H, halo and OC₁-C₃alkyl;        -   R¹¹ is independently selected from the group consisting of:            H, halo and C₁-C₃perhaloalkyl;

-   R^(c) is selected from the group consisting of:

-   R^(d) and R^(e) are independently H or C₁-C₃alkyl; and-   provided that at least one of R^(c), R^(d) and R^(e) are not H.-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

and R¹ is halo.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

and R¹ is C₁-C₃alkyl.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

and R² is C₁-C₃perhaloalkyl.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

and R² is halo.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

and R³ is H.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

R¹ is halo, R² is C₁-C₃perhaloalkyl, and R³ is H.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

and R¹, R², and R³ are halo.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

R¹ and R³ are halo and R² is H.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

R¹ and R² are halo and R³ is H.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

R⁴ is halo and R⁵ is C₁-C₃perhaloalkyl.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(b) is independently selected from the group    consisting of:

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(b) is independently selected from the group    consisting of:

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(b) is independently selected from the group    consisting of:

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(b) is

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(b) is

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(b) is

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(b) is

R⁶ and R⁷ are H and R⁸ is OCH₃.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(b) is

and R⁶, R⁷ and R⁸ are H.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(b) is

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(b) is

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(b) is

R⁹, R¹⁰ and R¹² are H and R¹¹ is F.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(b) is

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(b) is

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(c) is H or CH₃.-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(c) is selected from the group consisting of:

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(c) is:

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(c) is:

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(d) is CH₃.-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(e) is CH₃.-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(c) is CH₃ and R^(d) and R^(e) are H.-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(d) is CH₃ and R^(c) and R^(e) are H.-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(e) is CH₃ and R^(c) and R^(d) are H.-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

R¹ and R² are Cl, R^(c) is CH₃, R^(b) is

and R^(d), R^(e), R³, R⁶, R⁷ and R⁸ are H.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

R¹ and R² are Cl, R^(d) is CH₃, R^(b) is

and R^(c), R^(e), R³, R⁹, R¹⁰ and R¹² are H and R¹¹ is F.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

R¹ is Cl, and R² is CF₃, R^(d) is CH₃, R^(b) is

and R^(c), R^(e), R³, R⁹, R¹⁹ and R¹² are H and R¹¹ is F.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

R¹ and R² are Cl, R^(d) is CH₃, R^(b) is

and R⁸ is OCH₃, R^(c), R^(e), R³, R⁶, and R⁷ are H.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

R¹ is Cl, and R² is CF₃, R^(d) is CH₃, R^(c) is

R^(b) is

and R^(d), R^(e), and R³, are H.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

R¹ is Cl, and R² is CF₃, R^(d) is CH₃, R^(c) is

R^(b) is

and R^(d), R^(e), and R³, are H.

-   A further embodiment of the current invention is a compound of    Formula (I) wherein R^(a) is

R¹ is Cl, and R² is CF₃, R^(d) is CH₃, R^(c) is

R^(b) is

and R^(d), R^(e), and R³, are H.

-   A further embodiment of the current invention is a compound as shown    below in Table 1.

TABLE 1 (2,3-dichlorophenyl)(8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2,3-dichlorophenyl)(8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone2-chloro-3-(trifluoromethyl)phenyl)(5-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(2,3-dichlorophenyl)(5-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(2-chloro-3-(trifluoromethyl)phenyl)(3-(4-fluorophenyl)-5-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone:(2,3-dichlorophenyl)(3-(4-fluorophenyl)-5-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(2-chloro-3-(trifluoromethyl)phenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(2,3-dichlorophenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(2,3-dichlorophenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2,3-dichlorophenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(3-chloro-2-(trifluoromethyl)pyridin-4-yl)(8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(2-chloro-3-(trifluoromethyl)phenyl)(8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2,3-dichlorophenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(2-fluoro-3-(trifluoromethyl)phenyl)(8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(6-methyl-3-(pyrazin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-(pyrazin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(furan-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(2-chloro-3-(trifluoromethyl)phenyl)(3-(4-fluorophenyl)-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(3-(3-fluoro-4-(trifluoromethyl)phenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)- yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(3-fluoro-4-(trifluoromethyl)phenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-(3,4,5-trifluorophenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(6-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2,3-dichlorophenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(2,3-dichlorophenyl)(5-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(2-chloro-3-(trifluoromethyl)phenyl)(8-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(2-chloro-3-(trifluoromethyl)phenyl)(8-methyl-3-(pyrazin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(2-chloro-3-(trifluoromethyl)phenyl)(3-(4-chlorophenyl)-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(3-(2-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(2-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichloro-4-fluorophenyl)(3-(2-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(3-(3-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(3-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichloro-4-fluorophenyl)(3-(3-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(3-(2,3-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(2,3-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichloro-4-fluorophenyl)(3-(2,3-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(3-(3,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone.(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(3,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichloro-4-fluorophenyl)(3-(3,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(3-(2,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(2,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichloro-4-fluorophenyl)(3-(2,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(3-(6-fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(3-(4-methoxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(2-chlorophenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(3,4-difluoro-2-methylphenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(2-chloro-4-fluorophenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(2,3-dichloropyridin-4-yl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(3-cyclohexyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2,3-dichlorophenyl)methanone(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclohexyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(3-cyclohexyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2,3-dichloro-4-fluorophenyl)methanone(3-cyclopropyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2,3-dichlorophenyl)methanone(3-cyclopropyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2,3-dichloro-4-fluorophenyl)methanone(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclopropyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(3-(4-fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(3-(5-fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(5-fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin- 7(8H)-yl)methanone((S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(5-methoxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)- yl)methanone(S)-(2,3-dichlorophenyl)(3-(5-methoxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(3-(5-fluoropyrimidin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(3-(5-fluoropyrimidin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(±)-(2-chloro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclopropyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclopropyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(5-methoxypyrimidin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(±)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(furan-2-yl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(±)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(1-hydroxyethyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(3-(tert-butyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2-chloro-3-(trifluoromethyl)phenyl)methanone(S)-(3-(tert-butyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2-chloro-3-(trifluoromethyl)phenyl)methanone(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(furan-2-yl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(furan-2-yl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(±)-(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-ethyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-ethyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-isopropyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-isopropyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(±)-(2,3-dichlorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-(pyriclin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-(pyriclin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclobutyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclobutyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R*)-(2-chloro-4-fluoro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S*)-(2-chloro-4-fluoro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2-chloro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R*)-(3-chloro-2-(trifluoromethyl)pyridin-4-yl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S*)-(3-chloro-2-(trifluoromethyl)pyridin-4-yl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(±)-(2-chloro-3-(trifluoromethyl)phenyl)(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2,3-dichlorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2,3-dichlorophenyl)(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclopropyl-8-(4-fluorophenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclopropyl-8-(4-fluorophenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(difluoromethyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(difluoromethyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2,3-dichlorophenyl)(3-(difluoromethyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(3-(difluoromethyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2,3-dichlorophenyl)(3-methyl-8-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(3-methyl-8-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2-chloro-3-(trifluoromethyl)phenyl)(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-3-(trifluoromethyl)phenyl)(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2-methyl-3-(trifluoromethyl)phenyl)methanone(S)-(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2-methyl-3-(trifluoromethyl)phenyl)methanone(R)-(2-chloro-4-fluorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-chloro-4-fluorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2,4-dichlorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,4-dichlorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2-methyl-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-methyl-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2,3-dichloro-4-fluorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichloro-4-fluorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(±)-(8-(1H-pyrazol-5-yl)-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]thazolo[4,3-a]pyrazin-7(8H)-yl)(2-chloro-3-(trifluoromethyl)phenyl)methanone(±)-(2-chloro-3-(trifluoromethyl)phenyl)(8-(pyridin-3-yl)-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(R)-(2-fluoro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2-fluoro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(±)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(±)-benzyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]thazolo[4,3-a]pyrazin-7(8H)-yl)(2-chloro-3-(trifluoromethyl)phenyl)methanone.S)-(2,3-dichlorophenyl)(3-(4-hydroxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(3-(4-[¹¹C]methoxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(S)-(2,3-dichlorophenyl)(3-(4-[¹⁸F]fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

An additional embodiment of the invention is a pharmaceuticalcomposition comprising and effective amount of at least one compound inTable 1 and at least one pharmaceutically acceptable excipient.

Also within the scope of the invention are enantiomers and diastereomersof the compounds of Formula I. Also within the scope of the inventionare the pharmaceutically acceptable salts of the compounds of Formula I,as well as the pharmaceutically acceptable salts of the enantiomers anddiastereomers of the compounds of Formula I. Also within the scope ofthe invention are isotopic variations of compounds of Formula I, suchas, e.g., deuterated compounds of Formula I.

An additional embodiment of the invention is a method of treating asubject suffering from or diagnosed with a disease, disorder, or medicalcondition mediated by P2X7 receptor activity, comprising administeringto a subject in need of such treatment an effective amount of at leastone compound selected from compounds of Formula (I):

and enantiomers or diastereomers thereof;

and pharmaceutically acceptable salts thereof;

wherein:

R^(a) is

-   -   R¹ is halo or C₁-C₃alkyl;    -   R² is independently selected from the group consisting of: H,        halo, and C₁-C₃perhaloalkyl;    -   R³ is H or halo;    -   R⁴ is halo,    -   R⁵ is halo or C₁-C₃perhaloalkyl;

-   R^(b) is independently selected from the group consisting of:

Wherein:

-   -   R⁶, R⁹, R¹⁰, R¹², R¹⁴ are independently H or halo;    -   R⁷, R⁸, R¹³ is independently selected from the group consisting        of: H, halo and OC₁-C₃alkyl;    -   R¹¹ is independently selected from the group consisting of: H,        halo and C₁-C₃perhaloalkyl;

-   R^(c) is selected from the group consisting of:

-   R^(d) and R^(e) are independently H or C₁-C₃alkyl; and-   provided that at least one of R^(c), R^(d) and R^(e) are not H.

In preferred embodiments of the inventive method, the disease, disorder,or medical condition is selected from: diseases of the autoimmune andinflammatory system (Arulkumaran, N. et al. Expert Opin. Invetig Drugs,2011, July; 20(7):897-915) [examples of diseases of the autoimmune andinflammatory system include rheumatoid arthritis, osteoarthritis,interstitial cystitis (Martins J P, et. al., Br J Pharmacol. 2012January; 165(1):183-96), psoriasis (Killeen, M. E., et al., J Immunol.2013 Apr. 15; 190(8):4324-36), septic shock, sepsis, allergicdermatitis, asthma (examples of asthma include allergic asthma, mild tosevere asthma, and steroid resistant asthma), idiopathic pulmonaryfibrosis, allergic rhinitis, chronic obstructive pulmonary disease andairway hyper-responsiveness]; diseases of the nervous and neuro-immunesystem [examples of diseases of the nervous and neuro-immune systeminclude acute and chronic pain (examples of acute and chronic paininclude neuropathic pain, inflammatory pain, migraine, spontaneous pain(examples of spontaneous pain include opioid induced pain, diabeticneuropathy, postherpetic neuralgia, low back pain, chemotherapy-inducedneuropathic pain, fibromyalgia) (Romagnoli, R, et. al., Expert Opin.Ther. Targets, 2008, 12(5), 647-661)], and diseases involved with, andwithout, neuroinflammation of the Central Nervous System (CNS) [examplesof diseases involved with, and without, neuroinflammation of the CentralNervous System (CNS) include mood disorders (examples of mood disordersinclude major depression, major depressive disorder, treatment resistantdepression, bipolar disorder, anxious depression, anxiety) (Friedle, SA, et. al., Recent Patents on CNS Drug Discovery, 2010, 5, 35-45,Romagnoli, R, et. al., 2008), cognition, sleep disorders, multiplesclerosis (Sharp A J, et. al., J Neuroinflammation. 2008 Aug. 8; 5:33,Oyanguren-Desez O, et. al., Cell Calcium. 2011 November; 50(5):468-72,Grygorowicz T, et. al., Neurochem Int. 2010 December; 57(7):823-9),epileptic seizures (Engel T, et. al., FASEB J. 2012 April;26(4):1616-28, Kim J E, et. al. Neurol Res. 2009 November; 31(9):982-8,Avignone E, et. al., J Neurosci. 2008 Sep. 10; 28(37):9133-44),Parkinson's disease (Marcellino D, et. al., J Neural Transm. 2010 June;117(6):681-7), schizophrenia, Alzheimer's disease (Diaz-Hernandez J I,et. al., Neurobiol Aging. 2012 August; 33(8):1816-28, Delarasse C, JBiol Chem. 2011 Jan. 28; 286(4):2596-606, Sanz J M, et. al., J Immunol.2009 Apr. 1; 182(7):4378-85), Huntington's disease (Diaz-Hernández M,et. Al., FASEB J. 2009 June; 23(6):1893-906), Amyotrophic LateralSclerosis, autism, spinal cord injury,cerebral ischemia/traumatic braininjury (Chu K, et. al., J Neuroinflammation. 2012 Apr. 18; 9:69, ArbeloaJ, et. al, Neurobiol Dis. 2012 March; 45(3):954-61) and stress-relateddisorders].

In addition, P2X7 intervention may be beneficial in diseases of thecardiovascular, metabolic, gastrointestinal and urogenital systems[examples of diseases of the cardiovascular, metabolic, gastrointestinaland urogenital systems include diabetes (Arterioscler Thromb Vasc Biol.2004 July; 24(7):1240-5, J Cell Physiol. 2013 January; 228(1):120-9),diabetes mellitus, thrombosis (Furlan-Freguia C, et. al., J Clin Invest.2011 July; 121(7):2932-44, Vergani, A. et al., Diabetes, 2013, 62,1665-1675), irritable bowel disease, irritable bowel syndrome, (JImmunol. 2011 Aug. 1; 187(3):1467-74. Epub 2011 Jun. 22), Crohn'sdisease, cardiovascular diseases (examples of cardiovascular diseaseinclude hypertension (Ji X, et. al., Am J Physiol Renal Physiol. 2012October; 303(8):F1207-15), myocardial infarction, ischemic heartdisease, ischemia) ureteric obstruction, lower urinary tract syndrome(Br J Pharmacol. 2012 January; 165(1):183-96), lower urinary tractdysfunction such as incontinence, and disease after cardiac transplant(Vergani, A. et al., Circulation. 2013; 127:463-475)].

P2X7 antagonism may also present a novel therapeutic strategy forskeletal disorders, (examples of skeletal disorders includeosteoporosis/osteopetrosis) and may also modulate secretory function ofexocrine glands.

It is also hypothesized that modulation of the P2X7 receptor may also bebeneficial in conditions such as: glaucoma, Glomerulonephritis, Chaga'sDisease, chlamydia, neuroblastoma, Tuberculosis, Polycystic KidneyDisease, cancer, and acne (Thiboutot, D. M. J Investigative Dermatology,2014, 134, 595-597).

An additional embodiment of the invention is a method of treating asubject suffering from or diagnosed with a disease, disorder, or medicalcondition mediated by P2X7 receptor activity, wherein the disease,disorder, or medical condition is selected from the group consisting of:diseases of the autoimmune and inflammatory system [examples of diseasesof the autoimmune and inflammatory system include rheumatoid arthritis,osteoarthritis, interstitial cystitis, psoriasis, septic shock, sepsis,allergic dermatitis, asthma (examples of asthma include allergic asthma,mild to severe asthma, and steroid resistant asthma), idiopathicpulmonary fibrosis, allergic rhinitis, chronic obstructive pulmonarydisease and airway hyper-responsivenes]; diseases of the nervous andneuro-immune system [examples of diseases of the nervous andneuro-immune system include acute and chronic pain (examples of acuteand chronic pain include neuropathic pain, inflammatory pain, migraine,spontaneous pain (examples of spontaneous pain include opioid inducedpain, diabetic neuropathy, postherpetic neuralgia, low back pain,chemotherapy-induced neuropathic pain, fibromyalgia)]; diseases involvedwith, and without, neuroinflammation of the Central Nervous System (CNS)[examples of diseases involved with, and without, neuroinflammation ofthe Central Nervous System (CNS) include mood disorders (examples ofmood disorders include major depression, major depressive disorder,treatment resistant depression, bipolar disorder, anxious depression,anxiety), cognition, sleep disorders, multiple sclerosis, epilepticseizures, Parkinson's disease, schizophrenia, Alzheimer's disease,Huntington's disease, Amyotrophic Lateral Sclerosis, autism, spinal cordinjury and cerebral ischemia/traumatic brain injury, and stress-relateddisorders]; diseases of the cardiovascular, metabolic, gastrointestinaland urogenital systems [examples of diseases of the cardiovascular,metabolic, gastrointestinal and urogenital systems include diabetes,diabetes mellitus, thrombosis, irritable bowel disease, irritable bowelsyndrome, Crohn's disease, cardiovascular diseases (examples ofcardiovascular disease include hypertension, myocardial infarction,ischemic heart disease, ischemia) ureteric obstruction, lower urinarytract syndrome, lower urinary tract dysfunction such as incontinence,and disease after cardiac transplantation]; skeletal disorders,(examples of skeletal disorders include osteoporosis/osteopetrosis) anddiseases involving the secretory function of exocrine glands anddiseases such as glaucoma, Glomerulonephritis, Chaga's Disease,chlamydia, neuroblastoma, Tuberculosis, Polycystic Kidney Disease,cancer, and acne.

An additional embodiment of the invention is a method of treating asubject suffering from or diagnosed with a disease, disorder, or medicalcondition mediated by P2X7 receptor activity wherein the disease,disorder or medical condition is a disease involved with, and without,neuroinflammation of the Central Nervous System (CNS).

An additional embodiment of the invention is a method of treating asubject suffering from or diagnosed with a disease involved with, andwithout, neuroinflammation of the Central Nervous System (CNS) whereinthe disease, disorder or medical condition is a mood disorder.

An additional embodiment of the invention is a method of treating asubject suffering from a mood disorder wherein the mood disorder istreatment resistant depression.

Additional embodiments, features, and advantages of the invention willbe apparent from the following detailed description and through practiceof the invention.

The invention may be more fully appreciated by reference to thefollowing description, including the following glossary of terms and theconcluding examples. For the sake of brevity, the disclosures of thepublications, including patents, cited in this specification are hereinincorporated by reference.

As used herein, the terms “including”, “containing” and “comprising” areused herein in their open, non-limiting sense.

The term “alkyl” refers to a straight- or branched-chain alkyl grouphaving from 1 to 12 carbon atoms in the chain. Examples of alkyl groupsinclude methyl (Me, which also may be structurally depicted by thesymbol, “/”), ethyl (Et), n-propyl, isopropyl, butyl, isobutyl,sec-butyl, tert-butyl (tBu), pentyl, isopentyl, tert-pentyl, hexyl,isohexyl, and groups that in light of the ordinary skill in the art andthe teachings provided herein would be considered equivalent to any oneof the foregoing examples. The term C₁-C₃ alkyl as used here refers to astraight- or branched-chain alkyl group having from 1 to 3 carbon atomsin the chain. The term C₁-C₄ alkyl as used here refers to a straight- orbranched-chain alkyl group having from 1 to 4 carbon atoms in the chain.

The term “alkoxy” includes a straight chain or branched alkyl group witha terminal oxygen linking the alkyl group to the rest of the molecule.Alkoxy includes methoxy, ethoxy, propoxy, isopropoxy, butoxy, t-butoxy,pentoxy and so on.

The term “alkalkoxy” refers to the group alkyl-O-alkyl, where alkyl isdefined above. Such groups include methylenemethoxy (—CH₂OCH₃) andethylenemethoxy (—CH₂CH₂OCH₃).

The terms “hydroxyl” and “hydroxy” refer to an —OH group.

The term “cycloalkyl” refers to a saturated carbocycle having from 3 to6 ring atoms per carbocycle. Illustrative examples of cycloalkyl groupsinclude the following entities, in the form of properly bonded moieties:

The term “C₃-C₄ cycloalkyl” as used here refers to a saturatedcarbocycle having from 3 to 4 ring atoms.

A “heterocycloalkyl” refers to a monocyclic ring structure that issaturated and has from 4 to 6 ring atoms per ring structure selectedfrom carbon atoms and one nitrogen atom. Illustrative entities, in theform of properly bonded moieties, include:

The term “aryl” refers to a monocyclic, aromatic carbocycle (ringstructure having ring atoms that are all carbon) having 6 atoms perring. (Carbon atoms in the aryl groups are sp² hybridized.)

The term “phenyl” represents the following moiety:

The term “heteroaryl” refers to a monocyclic or fused bicyclicheterocycle (ring structure having ring atoms selected from carbon atomsand up to four heteroatoms selected from nitrogen, oxygen, and sulfur)having from 3 to 9 ring atoms per heterocycle. Illustrative examples ofheteroaryl groups include the following entities, in the form ofproperly bonded moieties:

Those skilled in the art will recognize that the species of heteroaryl,cycloalkyl, aryl and heterocycloalkyl groups listed or illustrated aboveare not exhaustive, and that additional species within the scope ofthese defined terms may also be selected.

The term “cyano” refers to the group —CN.

The term “halo” represents chloro, fluoro, bromo or iodo.

The term “perhaloalkyl” refers to a straight- or branched-chain alkylgroup having from 1 to 4 carbon atoms in the chain optionallysubstituting hydrogens with halogens. Examples of perhaloalkyl groupsinclude trifluoromethyl (CF₃), difluoromethyl (CF₂H), monofluoromethyl(CH₂F), pentafluoroethyl (CF₂CF₃), tetrafluoroethyl(CHFCF₃),monofluoroethyl (CH₂CH₂F), trifluoroethyl (CH₂CF₃),tetrafluorotrifluoromethylethyl (—CF(CF₃)₂), and groups that in light ofthe ordinary skill in the art and the teachings provided herein would beconsidered equivalent to any one of the foregoing examples.

The term “perhaloalkoxy” refers to a straight- or branched-chain alkoxygroup having from 1 to 4 carbon atoms in the chain optionallysubstituting hydrogens with halogens. Examples of perhaloalkoxy groupsinclude trifluoromethoxy (OCF₃), difluoromethoxy (OCF₂H),monofluoromethoxy (OCH₂F), momofluoroethoxy (OCH₂CH₂F),pentafluoroethoxy (OCF₂CF₃), tetrafluoroethoxy (OCHFCF₃),trifluoroethoxy (OCH₂CF₃), tetrafluorotrifluoromethylethoxy(—OCF(CF₃)₂), and groups that in light of the ordinary skill in the artand the teachings provided herein would be considered equivalent to anyone of the foregoing examples.

The term “substituted” means that the specified group or moiety bearsone or more substituents. The term “unsubstituted” means that thespecified group bears no substituents. The term “optionally substituted”means that the specified group is unsubstituted or substituted by one ormore substituents. Where the term “substituted” is used to describe astructural system, the substitution is meant to occur at anyvalency-allowed position on the system. In cases where a specifiedmoiety or group is not expressly noted as being optionally substitutedor substituted with any specified substituent, it is understood thatsuch a moiety or group is intended to be unsubstituted.

The terms “para”, “meta”, and “ortho” have the meanings as understood inthe art. Thus, for example, a fully substituted phenyl group hassubstituents at both “ortho”(o) positions adjacent to the point ofattachment of the phenyl ring, both “meta” (m) positions, and the one“para” (p) position across from the point of attachment. To furtherclarify the position of substituents on the phenyl ring, the 2 differentortho positions will be designated as ortho and ortho′ and the 2different meta positions as meta and meta′ as illustrated below.

When referring to substituents on a pyridyl group, the terms “para”,“meta”, and “ortho” refer to the placement of a substituent relative tothe point of attachment of the pyridyl ring. For example the structurebelow is described as 4-pyridyl with the X substituent in the orthoposition and the Y substituent in the meta position:

To provide a more concise description, some of the quantitativeexpressions given herein are not qualified with the term “about”. It isunderstood that, whether the term “about” is used explicitly or not,every quantity given herein is meant to refer to the actual given value,and it is also meant to refer to the approximation to such given valuethat would reasonably be inferred based on the ordinary skill in theart, including equivalents and approximations due to the experimentaland/or measurement conditions for such given value. Whenever a yield isgiven as a percentage, such yield refers to a mass of the entity forwhich the yield is given with respect to the maximum amount of the sameentity that could be obtained under the particular stoichiometricconditions. Concentrations that are given as percentages refer to massratios, unless indicated differently.

The terms “buffered” solution or “buffer” solution are used hereininterchangeably according to their standard meaning. Buffered solutionsare used to control the pH of a medium, and their choice, use, andfunction is known to those of ordinary skill in the art. See, forexample, G. D. Considine, ed., Van Nostrand's Encyclopedia of Chemistry,p. 261, 5^(th) ed. (2005), describing, inter alia, buffer solutions andhow the concentrations of the buffer constituents relate to the pH ofthe buffer. For example, a buffered solution is obtained by adding MgSO₄and NaHCO₃ to a solution in a 10:1 w/w ratio to maintain the pH of thesolution at about 7.5.

Any formula given herein is intended to represent compounds havingstructures depicted by the structural formula as well as certainvariations or forms. In particular, compounds of any formula givenherein may have asymmetric centers and therefore exist in differentenantiomeric forms. All optical isomers of the compounds of the generalformula, and mixtures thereof, are considered within the scope of theformula. Thus, any formula given herein is intended to represent aracemate, one or more enantiomeric forms, one or more diastereomericforms, one or more atropisomeric forms, and mixtures thereof.Furthermore, certain structures may exist as geometric isomers (i.e.,cis and trans isomers), as tautomers, or as atropisomers.

It is also to be understood that compounds that have the same molecularformula but differ in the nature or sequence of bonding of their atomsor the arrangement of their atoms in space are termed “isomers.” Isomersthat differ in the arrangement of their atoms in space are termed “.”

Stereoisomers that are not mirror images of one another are termed“diastereomers” and those that are non-superimposable mirror images ofeach other are termed “enantiomers.” When a compound has an asymmetriccenter, for example, it is bonded to four different groups, and a pairof enantiomers is possible. An enantiomer can be characterized by theabsolute configuration of its asymmetric center and is described by theR-and S-sequencing rules of Cahn and Prelog, or by the manner in whichthe molecule rotates the plane of polarized light and designated asdextrorotatory or levorotatory (i.e., as (+)- or (−)-isomersrespectively). A chiral compound can exist as either an individualenantiomer or as a mixture thereof. A mixture containing equalproportions of the enantiomers is called a “racemic mixture.”

“Tautomers” refer to compounds that are interchangeable forms of aparticular compound structure, and that vary in the displacement ofhydrogen atoms and electrons. Thus, two structures may be in equilibriumthrough the movement of π electrons and an atom (usually H). Forexample, enols and ketones are tautomers because they are rapidlyinterconverted by treatment with either acid or base. Another example oftautomerism is the aci-and nitro-forms of phenyl nitromethane, that arelikewise formed by treatment with acid or base.

Tautomeric forms may be relevant to the attainment of the optimalchemical reactivity and biological activity of a compound of interest.

Compounds of the invention may also exist as “rotamers,” that is,conformational isomers that occur when the rotation leading to differentconformations is hindered, resulting in a rotational energy barrier tobe overcome to convert from one conformational isomer to another.

The compounds of this invention may possess one or more asymmetriccenters; such compounds can therefore be produced as individual (R)- or(S)-stereoisomers or as mixtures thereof.

Unless indicated otherwise, the description or naming of a particularcompound in the specification and claims is intended to include bothindividual enantiomers and mixtures, racemic or otherwise, thereof. Themethods for the determination of stereochemistry and the separation ofstereoisomers are well-known in the art.

Certain examples contain chemical structures that are depicted as anabsolute enantiomer but are intended to indicate enatiopure materialthat is of unknown configuration. In these cases (R*) or (S*) is used inthe name to indicate that the absolute stereochemistry of thecorresponding stereocenter is unknown. Thus, a compound designated as(R*) refers to an enantiopure compound with an absolute configuration ofeither (R) or (S). In cases where the absolute stereochemistry has beenconfirmed, the structures are named using (R) and (S).

The symbols

and

are used as meaning the same spatial arrangement in chemical structuresshown herein. Analogously, the symbols

and

are used as meaning the same spatial arrangement in chemical structuresshown herein.

Additionally, any formula given herein is intended to refer also tohydrates, solvates, and polymorphs of such compounds, and mixturesthereof, even if such forms are not listed explicitly. Certain compoundsof Formula (I) or pharmaceutically acceptable salts of compounds ofFormula (I) may be obtained as solvates. Solvates include those formedfrom the interaction or complexation of compounds of the invention withone or more solvents, either in solution or as a solid or crystallineform. In some embodiments, the solvent is water and the solvates arehydrates. In addition, certain crystalline forms of compounds of Formula(I) or pharmaceutically acceptable salts of compounds of Formula (I) maybe obtained as co-crystals. In certain embodiments of the invention,compounds of Formula (I) were obtained in a crystalline form. In otherembodiments, crystalline forms of compounds of Formula (I) were cubic innature. In other embodiments, pharmaceutically acceptable salts ofcompounds of Formula (I) were obtained in a crystalline form. In stillother embodiments, compounds of Formula (I) were obtained in one ofseveral polymorphic forms, as a mixture of crystalline forms, as apolymorphic form, or as an amorphous form. In other embodiments,compounds of Formula (I) convert in solution between one or morecrystalline forms and/or polymorphic forms.

Reference to a compound herein stands for a reference to any one of: (a)the actually recited form of such compound, and (b) any of the forms ofsuch compound in the medium in which the compound is being consideredwhen named. For example, reference herein to a compound such as R—COOH,encompasses reference to any one of, for example, R—COOH_((s)),R—COOH_((sol)), and R—COO⁻ _((sol)). In this example, R—COOH_((s))refers to the solid compound, as it could be for example in a tablet orsome other solid pharmaceutical composition or preparation;R—COOH_((sol)) refers to the undissociated form of the compound in asolvent; and R—COO⁻ _((sol)) refers to the dissociated form of thecompound in a solvent, such as the dissociated form of the compound inan aqueous environment, whether such dissociated form derives fromR—COOH, from a salt thereof, or from any other entity that yields R—COO⁻upon dissociation in the medium being considered. In another example, anexpression such as “exposing an entity to compound of formula R—COOH”refers to the exposure of such entity to the form, or forms, of thecompound R—COOH that exists, or exist, in the medium in which suchexposure takes place. In still another example, an expression such as“reacting an entity with a compound of formula R—COOH” refers to thereacting of (a) such entity in the chemically relevant form, or forms,of such entity that exists, or exist, in the medium in which suchreacting takes place, with (b) the chemically relevant form, or forms,of the compound R—COOH that exists, or exist, in the medium in whichsuch reacting takes place. In this regard, if such entity is for examplein an aqueous environment, it is understood that the compound R—COOH isin such same medium, and therefore the entity is being exposed tospecies such as R—COOH_((aq)) and/or R—COO⁻ _((aq)), where the subscript“(aq)” stands for “aqueous” according to its conventional meaning inchemistry and biochemistry. A carboxylic acid functional group has beenchosen in these nomenclature examples; this choice is not intended,however, as a limitation but it is merely an illustration. It isunderstood that analogous examples can be provided in terms of otherfunctional groups, including but not limited to hydroxyl, basic nitrogenmembers, such as those in amines, and any other group that interacts ortransforms according to known manners in the medium that contains thecompound. Such interactions and transformations include, but are notlimited to, dissociation, association, tautomerism, solvolysis,including hydrolysis, solvation, including hydration, protonation, anddeprotonation. No further examples in this regard are provided hereinbecause these interactions and transformations in a given medium areknown by any one of ordinary skill in the art.

In another example, a zwitterionic compound is encompassed herein byreferring to a compound that is known to form a zwitterion, even if itis not explicitly named in its zwitterionic form. Terms such aszwitterion, zwitterions, and their synonyms zwitterionic compound(s) arestandard IUPAC-endorsed names that are well known and part of standardsets of defined scientific names. In this regard, the name zwitterion isassigned the name identification CHEBI:27369 by the Chemical Entities ofBiological Interest (ChEBI) dictionary of molecular entities. Asgenerally well known, a zwitterion or zwitterionic compound is a neutralcompound that has formal unit charges of opposite sign. Sometimes thesecompounds are referred to by the term “inner salts”. Other sources referto these compounds as “dipolar ions”, although the latter term isregarded by still other sources as a misnomer. As a specific example,aminoethanoic acid (the amino acid glycine) has the formula H₂NCH₂COOH,and it exists in some media (in this case in neutral media) in the formof the zwitterion ⁺H₃NCH₂COO⁻. Zwitterions, zwitterionic compounds,inner salts and dipolar ions in the known and well established meaningsof these terms are within the scope of this invention, as would in anycase be so appreciated by those of ordinary skill in the art. Becausethere is no need to name each and every embodiment that would berecognized by those of ordinary skill in the art, no structures of thezwitterionic compounds that are associated with the compounds of thisinvention are given explicitly herein. They are, however, part of theembodiments of this invention. No further examples in this regard areprovided herein because the interactions and transformations in a givenmedium that lead to the various forms of a given compound are known byany one of ordinary skill in the art.

Any formula given herein is also intended to represent unlabeled formsas well as isotopically labeled forms of the compounds. Isotopicallylabeled compounds have structures depicted by the formulas given hereinexcept that one or more atoms are replaced by an atom having a selectedatomic mass or mass number. Examples of isotopes that can beincorporated into compounds of the invention include isotopes ofhydrogen, carbon, nitrogen, oxygen, phosphorus, sulfur, fluorine,chlorine, and iodine such as ²H, ³H, ¹¹C, ¹³C, ¹⁴C, ¹⁵N, ¹⁸O, ¹⁷O, ³¹P,³²P, ³⁵S, ¹⁸F, ³⁶Cl, ¹²⁵I, respectively. Such isotopically labeledcompounds are useful in metabolic studies (preferably with ¹⁴C),reaction kinetic studies (with, for example ²H or ³H), detection orimaging techniques [such as positron emission tomography (PET) orsingle-photon emission computed tomography (SPECT)] including drug orsubstrate tissue distribution assays, or in radioactive treatment ofpatients. In particular, an ¹⁸F or ¹¹C labeled compound may beparticularly preferred for PET or SPECT studies. Further, substitutionwith heavier isotopes such as deuterium (i.e., ²H) may afford certaintherapeutic advantages resulting from greater metabolic stability, forexample increased in vivo half-life or reduced dosage requirements.Isotopically labeled compounds of this invention and prodrugs thereofcan generally be prepared by carrying out the procedures disclosed inthe schemes or in the examples and preparations described below bysubstituting a readily available isotopically labeled reagent for anon-isotopically labeled reagent.

When referring to any formula given herein, the selection of aparticular moiety from a list of possible species for a specifiedvariable is not intended to define the same choice of the species forthe variable appearing elsewhere. In other words, where a variableappears more than once, the choice of the species from a specified listis independent of the choice of the species for the same variableelsewhere in the formula, unless stated otherwise.

According to the foregoing interpretive considerations on assignmentsand nomenclature, it is understood that explicit reference herein to aset implies, where chemically meaningful and unless indicated otherwise,independent reference to embodiments of such set, and reference to eachand every one of the possible embodiments of subsets of the set referredto explicitly.

The invention includes also pharmaceutically acceptable salts of thecompounds of Formula (I), preferably of those described above and of thespecific compounds exemplified herein, and methods of treatment usingsuch salts.

The term “pharmaceutically acceptable” means approved or approvable by aregulatory agency of Federal or a state government or the correspondingagency in countries other than the United States, or that is listed inthe U.S. Pharmcopoeia or other generally recognized pharmacopoeia foruse in animals, and more particularly, in humans.

A “pharmaceutically acceptable salt” is intended to mean a salt of afree acid or base of compounds represented by Formula (I) that arenon-toxic, biologically tolerable, or otherwise biologically suitablefor administration to the subject. It should possess the desiredpharmacological activity of the parent compound. See, generally, G. S.Paulekuhn, et al., “Trends in Active Pharmaceutical Ingredient SaltSelection based on Analysis of the Orange Book Database”, J. Med. Chem.,2007, 50:6665-72, S. M. Berge, et al., “Pharmaceutical Salts”, J PharmSci., 1977, 66:1-19, and Handbook of Pharmaceutical Salts, Properties,Selection, and Use, Stahl and Wermuth, Eds., Wiley-VCH and VHCA, Zurich,2002. Examples of pharmaceutically acceptable salts are those that arepharmacologically effective and suitable for contact with the tissues ofpatients without undue toxicity, irritation, or allergic response. Acompound of Formula (I) may possess a sufficiently acidic group, asufficiently basic group, or both types of functional groups, andaccordingly react with a number of inorganic or organic bases, andinorganic and organic acids, to form a pharmaceutically acceptable salt.

Examples of pharmaceutically acceptable salts include sulfates,pyrosulfates, bisulfates, sulfites, bisulfites, phosphates,monohydrogen-phosphates, dihydrogenphosphates, metaphosphates,pyrophosphates, chlorides, bromides, iodides, acetates, propionates,decanoates, caprylates, acrylates, formates, isobutyrates, caproates,heptanoates, propiolates, oxalates, malonates, succinates, suberates,sebacates, fumarates, maleates, butyne-1,4-dioates, hexyne-1,6-dioates,benzoates, chlorobenzoates, methyl benzoates, dinitrobenzoates,hydroxybenzoates, methoxybenzoates, phthalates, sulfonates,xylenesulfonates, phenylacetates, phenylpropionates, phenylbutyrates,citrates, lactates, γ-hydroxybutyrates, glycolates, tartrates,methane-sulfonates, propanesulfonates, naphthalene-1-sulfonates,naphthalene-2-sulfonates, and mandelates.

When the compounds of Formula (I) contain a basic nitrogen, the desiredpharmaceutically acceptable salt may be prepared by any suitable methodavailable in the art. For example, treatment of the free base with aninorganic acid, such as hydrochloric acid, hydrobromic acid, sulfuricacid, sulfamic acid, nitric acid, boric acid, phosphoric acid, and thelike, or with an organic acid, such as acetic acid, phenylacetic acid,propionic acid, stearic acid, lactic acid, ascorbic acid, maleic acid,hydroxymaleic acid, isethionic acid, succinic acid, valeric acid,fumaric acid, malonic acid, pyruvic acid, oxalic acid, glycolic acid,salicylic acid, oleic acid, palmitic acid, lauric acid, a pyranosidylacid, such as glucuronic acid or galacturonic acid, an alpha-hydroxyacid, such as mandelic acid, citric acid, or tartaric acid, an aminoacid, such as aspartic acid, glutaric acid or glutamic acid, an aromaticacid, such as benzoic acid, 2-acetoxybenzoic acid, naphthoic acid, orcinnamic acid, a sulfonic acid, such as laurylsulfonic acid,p-toluenesulfonic acid, methanesulfonic acid, ethanesulfonic acid, anycompatible mixture of acids such as those given as examples herein, andany other acid and mixture thereof that are regarded as equivalents oracceptable substitutes in light of the ordinary level of skill in thistechnology.

The invention may be more fully appreciated by reference to thefollowing description, including the following glossary of terms and theconcluding examples. For the sake of brevity, the disclosures of thepublications, including patents, cited in this specification are hereinincorporated by reference.

As used herein, the terms “including”, “containing” and “comprising” areused herein in their open, non-limiting sense.

When the compound of Formula (I) is an acid, such as a carboxylic acidor sulfonic acid, the desired pharmaceutically acceptable salt may beprepared by any suitable method, for example, treatment of the free acidwith an inorganic or organic base, such as an amine (primary, secondaryor tertiary), an alkali metal hydroxide, alkaline earth metal hydroxide,any compatible mixture of bases such as those given as examples herein,and any other base and mixture thereof that are regarded as equivalentsor acceptable substitutes in light of the ordinary level of skill inthis technology. Illustrative examples of suitable salts include organicsalts derived from amino acids, such as N-methyl-D-glucamine, lysine,choline, glycine and arginine, ammonia, carbonates, bicarbonates,primary, secondary, and tertiary amines, and cyclic amines, such astromethamine, benzylamines, pyrrolidines, piperidine, morpholine, andpiperazine, and inorganic salts derived from sodium, calcium, potassium,magnesium, manganese, iron, copper, zinc, aluminum, and lithium.

The invention also relates to pharmaceutically acceptable prodrugs ofthe compounds of Formula (I), and treatment methods employing suchpharmaceutically acceptable prodrugs. The term “prodrug” means aprecursor of a designated compound that, following administration to asubject, yields the compound in vivo via a chemical or physiologicalprocess such as solvolysis or enzymatic cleavage, or under physiologicalconditions (e.g., a prodrug on being brought to physiological pH isconverted to the compound of Formula (I). A “pharmaceutically acceptableprodrug” is a prodrug that is non-toxic, biologically tolerable, andotherwise biologically suitable for administration to the subject.Illustrative procedures for the selection and preparation of suitableprodrug derivatives are described, for example, in “Design of Prodrugs”,ed. H. Bundgaard, Elsevier, 1985.

Exemplary prodrugs include compounds having an amino acid residue, or apolypeptide chain of two or more (e.g., two, three or four) amino acidresidues, covalently joined through an amide or ester bond to a freeamino, hydroxyl, or carboxylic acid group of a compound of Formula (I,IIa or IIb). Examples of amino acid residues include the twentynaturally occurring amino acids, commonly designated by three lettersymbols, as well as 4-hydroxyproline, hydroxylysine, demosine,isodemosine, 3-methylhistidine, norvalin, beta-alanine,gamma-aminobutyric acid, citrulline homocysteine, homoserine, ornithineand methionine sulfone.

Additional types of prodrugs may be produced, for instance, byderivatizing free carboxyl groups of structures of Formula (I) as amidesor alkyl esters. Examples of amides include those derived from ammonia,primary C₁₋₆alkyl amines and secondary di(C₁₋₆alkyl) amines. Secondaryamines include 5- or 6-membered heterocycloalkyl or heteroaryl ringmoieties. Examples of amides include those that are derived fromammonia, C₁₋₃alkyl primary amines, and di(C₁₋₂alkyl)amines. Examples ofesters of the invention include C₁₋₇alkyl, C₅₋₇cycloalkyl, phenyl, andphenyl(C₁₋₆alkyl) esters. Preferred esters include methyl esters.Prodrugs may also be prepared by derivatizing free hydroxy groups usinggroups including hemisuccinates, phosphate esters,dimethylaminoacetates, and phosphoryloxymethyloxycarbonyls, followingprocedures such as those outlined in Fleisher et al., Adv. Drug DeliveryRev. 1996, 19, 115-130. Carbamate derivatives of hydroxy and aminogroups may also yield prodrugs. Carbonate derivatives, sulfonate esters,and sulfate esters of hydroxy groups may also provide prodrugs.Derivatization of hydroxy groups as (acyloxy)methyl and (acyloxy)ethylethers, wherein the acyl group may be an alkyl ester, optionallysubstituted with one or more ether, amine, or carboxylic acidfunctionalities, or where the acyl group is an amino acid ester asdescribed above, is also useful to yield prodrugs. Prodrugs of this typemay be prepared as described in Robinson et al., J Med Chem. 1996, 39(1), 10-18. Free amines can also be derivatized as amides, sulfonamidesor phosphonamides. All of these prodrug moieties may incorporate groupsincluding ether, amine, and carboxylic acid functionalities.

The present invention also relates to pharmaceutically activemetabolites of the compounds of Formula (I), which may also be used inthe methods of the invention. A “pharmaceutically active metabolite”means a pharmacologically active product of metabolism in the body of acompound of Formula (I, IIa or IIb) or salt thereof. Prodrugs and activemetabolites of a compound may be determined using routine techniquesknown or available in the art. See, e.g., Bertolini, et al., J Med Chem.1997, 40, 2011-2016; Shan, et al., J Pharm Sci. 1997, 86 (7), 765-767;Bagshawe, Drug Dev Res. 1995, 34, 220-230; Bodor, Adv Drug Res. 1984,13, 224-331; Bundgaard, Design of Prodrugs (Elsevier Press, 1985); andLarsen, Design and Application of Prodrugs, Drug Design and Development(Krogsgaard-Larsen, et al., eds., Harwood Academic Publishers, 1991).

The compounds of Formula (I) and their pharmaceutically acceptablesalts, pharmaceutically acceptable prodrugs, and pharmaceutically activemetabolites of the present invention are useful as modulators of theP2X7 receptor in the methods of the invention. As such modulators, thecompounds may act as antagonists, agonists, or inverse agonists. Theterm “modulators” include both inhibitors and activators, where“inhibitors” refer to compounds that decrease, prevent, inactivate,desensitize, or down-regulate the P2X7 receptor expression or activity,and “activators” are compounds that increase, activate, facilitate,sensitize, or up-regulate P2X7 receptor expression or activity.

The term “treat”, “treatment” or “treating”, as used herein, is intendedto refer to administration of an active agent or composition of theinvention to a subject for the purpose of affecting a therapeutic orprophylactic benefit through modulation of P2X7 receptor activity.Treating includes reversing, ameliorating, alleviating, inhibiting theprogress of, lessening the severity of, or preventing a disease,disorder, or condition, or one or more symptoms of such disease,disorder or condition mediated through modulation of P2X7 receptoractivity. The term “subject” refers to a mammalian patient in need ofsuch treatment, such as a human.

Accordingly, the invention relates to methods of using the compoundsdescribed herein to treat subjects diagnosed with or suffering from adisease, disorder, or condition mediated by P2X7 receptor activity, suchas: diseases of the autoimmune and inflammatory system [examples ofdiseases of the autoimmune and inflammatory system include rheumatoidarthritis, osteoarthritis, interstitial cystitis, psoriasis, septicshock, sepsis, allergic dermatitis, asthma (examples of asthma includeallergic asthma, mild to severe asthma, and steroid resistant asthma),idiopathic pulmonary fibrosis, allergic rhinitis, chronic obstructivepulmonary disease and airway hyper-responsivenes]; diseases of thenervous and neuro-immune system [examples of diseases of the nervous andneuro-immune system include acute and chronic pain (examples of acuteand chronic pain include neuropathic pain, inflammatory pain, migraine,spontaneous pain (examples of spontaneous pain include opioid inducedpain, diabetic neuropathy, postherpetic neuralgia, low back pain,chemotherapy-induced neuropathic pain, fibromyalgia)]; diseases involvedwith, and without, neuroinflammation of the Central Nervous System (CNS)[examples of diseases involved with, and without, neuroinflammation ofthe Central Nervous System (CNS) include mood disorders (examples ofmood disorders include major depression, major depressive disorder,treatment resistant depression, bipolar disorder, anxious depression,anxiety), cognition, sleep disorders, multiple sclerosis, epilepticseizures, Parkinson's disease, schizophrenia, Alzheimer's disease,Huntington's disease, Amyotrophic Lateral Sclerosis, autism, spinal cordinjury and cerebral ischemia/traumatic brain injury, and stress-relateddisorders]; diseases of the cardiovascular, metabolic, gastrointestinaland urogenital systems [examples of diseases of the cardiovascular,metabolic, gastrointestinal and urogenital systems include diabetes,diabetes mellitus, thrombosis, irritable bowel disease, irritable bowelsyndrome, Crohn's disease, cardiovascular diseases (examples ofcardiovascular disease include hypertension, myocardial infarction,ischemic heart disease, ischemia) ureteric obstruction, lower urinarytract syndrome, lower urinary tract dysfunction such as incontinence,and disease after cardiac transplantation]; skeletal disorders,(examples of skeletal disorders include osteoporosis/osteopetrosis) anddiseases involving the secretory function of exocrine glands anddiseases such as glaucoma, Glomerulonephritis, Chaga's Disease,chlamydia, neuroblastoma, Tuberculosis, Polycystic Kidney Disease,cancer, and acne.

In treatment methods according to the invention, an effective amount ofa pharmaceutical agent according to the invention is administered to asubject suffering from or diagnosed as having such a disease, disorder,or condition. An “effective amount” means an amount or dose sufficientto generally bring about the desired therapeutic or prophylactic benefitin patients in need of such treatment for the designated disease,disorder, or condition. Effective amounts or doses of the compounds ofthe present invention may be ascertained by routine methods such asmodeling, dose escalation studies or clinical trials, and by taking intoconsideration routine factors, e.g., the mode or route of administrationor drug delivery, the pharmacokinetics of the compound, the severity andcourse of the disease, disorder, or condition, the subject's previous orongoing therapy, the subject's health status and response to drugs, andthe judgment of the treating physician. An example of a dose is in therange of from about 0.001 to about 200 mg of compound per kg ofsubject's body weight per day, preferably about 0.05 to 100 mg/kg/day,or about 1 to 35 mg/kg/day, in single or divided dosage units (e.g.,BID, TID, QID). For a 70-kg human, an illustrative range for a suitabledosage amount is from about 0.05 to about 7 g/day, or about 0.2 to about2.5 g/day.

Once improvement of the patient's disease, disorder, or condition hasoccurred, the dose may be adjusted for preventative or maintenancetreatment. For example, the dosage or the frequency of administration,or both, may be reduced as a function of the symptoms, to a level atwhich the desired therapeutic or prophylactic effect is maintained. Ofcourse, if symptoms have been alleviated to an appropriate level,treatment may cease. Patients may, however, require intermittenttreatment on a long-term basis upon any recurrence of symptoms.

In addition, the active agents of the invention may be used incombination with additional active ingredients in the treatment of theabove conditions. The additional active ingredients may becoadministered separately with an active agent of compounds of Tables 1or included with such an agent in a pharmaceutical composition accordingto the invention. In an exemplary embodiment, additional activeingredients are those that are known or discovered to be effective inthe treatment of conditions, disorders, or diseases mediated by P2X7activity, such as another P2X7 modulator or a compound active againstanother target associated with the particular condition, disorder, ordisease. The combination may serve to increase efficacy (e.g., byincluding in the combination a compound potentiating the potency oreffectiveness of an active agent according to the invention), decreaseone or more side effects, or decrease the required dose of the activeagent according to the invention.

The active agents of the invention are used, alone or in combinationwith one or more additional active ingredients, to formulatepharmaceutical compositions of the invention. A pharmaceuticalcomposition of the invention comprises: (a) an effective amount of atleast one active agent in accordance with the invention; and (b) apharmaceutically acceptable excipient.

A “pharmaceutically acceptable excipient” refers to a substance that isnon-toxic, biologically tolerable, and otherwise biologically suitablefor administration to a subject, such as an inert substance, added to apharmacological composition or otherwise used as a vehicle, carrier, ordiluent to facilitate administration of an agent and that is compatibletherewith. Examples of excipients include calcium carbonate, calciumphosphate, various sugars and types of starch, cellulose derivatives,gelatin, vegetable oils, and polyethylene glycols.

Delivery forms of the pharmaceutical compositions containing one or moredosage units of the active agents may be prepared using suitablepharmaceutical excipients and compounding techniques known or thatbecome available to those skilled in the art. The compositions may beadministered in the inventive methods by a suitable route of delivery,e.g., oral, parenteral, rectal, topical, or ocular routes, or byinhalation.

The preparation may be in the form of tablets, capsules, sachets,dragees, powders, granules, lozenges, powders for reconstitution, liquidpreparations, or suppositories. Preferably, the compositions areformulated for intravenous infusion, topical administration, or oraladministration.

For oral administration, the compounds of the invention can be providedin the form of tablets or capsules, or as a solution, emulsion, orsuspension. To prepare the oral compositions, the compounds may beformulated to yield a dosage of, e.g., from about 0.05 to about 100mg/kg daily, or from about 0.05 to about 35 mg/kg daily, or from about0.1 to about 10 mg/kg daily. For example, a total daily dosage of about5 mg to 5 g daily may be accomplished by dosing once, twice, three, orfour times per day.

Oral tablets may include a compound according to the invention mixedwith pharmaceutically acceptable excipients such as inert diluents,disintegrating agents, binding agents, lubricating agents, sweeteningagents, flavoring agents, coloring agents and preservative agents.Suitable inert fillers include sodium and calcium carbonate, sodium andcalcium phosphate, lactose, starch, sugar, glucose, methyl cellulose,magnesium stearate, mannitol, sorbitol, and the like. Exemplary liquidoral excipients include ethanol, glycerol, water, and the like. Starch,polyvinyl-pyrrolidone (PVP), sodium starch glycolate, microcrystallinecellulose, and alginic acid are suitable disintegrating agents. Bindingagents may include starch and gelatin. The lubricating agent, ifpresent, may be magnesium stearate, stearic acid or talc. If desired,the tablets may be coated with a material such as glyceryl monostearateor glyceryl distearate to delay absorption in the gastrointestinaltract, or may be coated with an enteric coating.

Capsules for oral administration include hard and soft gelatin capsules.To prepare hard gelatin capsules, compounds of the invention may bemixed with a solid, semi-solid, or liquid diluent. Soft gelatin capsulesmay be prepared by mixing the compound of the invention with water, anoil such as peanut oil or olive oil, liquid paraffin, a mixture of monoand di-glycerides of short chain fatty acids, polyethylene glycol 400,or propylene glycol.

Liquids for oral administration may be in the form of suspensions,solutions, emulsions or syrups or may be lyophilized or presented as adry product for reconstitution with water or other suitable vehiclebefore use. Such liquid compositions may optionally contain:pharmaceutically-acceptable excipients such as suspending agents (forexample, sorbitol, methyl cellulose, sodium alginate, gelatin,hydroxyethylcellulose, carboxymethylcellulose, aluminum stearate gel andthe like); non-aqueous vehicles, e.g., oil (for example, almond oil orfractionated coconut oil), propylene glycol, ethyl alcohol, or water;preservatives (for example, methyl or propyl p-hydroxybenzoate or sorbicacid); wetting agents such as lecithin; and, if desired, flavoring orcoloring agents.

The active agents of this invention may also be administered by non-oralroutes. For example, the compositions may be formulated for rectaladministration as a suppository. For parenteral use, includingintravenous, intramuscular, intraperitoneal, or subcutaneous routes, thecompounds of the invention may be provided in sterile aqueous solutionsor suspensions, buffered to an appropriate pH and isotonicity or inparenterally acceptable oil. Suitable aqueous vehicles include Ringer'ssolution and isotonic sodium chloride. Such forms will be presented inunit-dose form such as ampules or disposable injection devices, inmulti-dose forms such as vials from which the appropriate dose may bewithdrawn, or in a solid form or pre-concentrate that can be used toprepare an injectable formulation. Illustrative infusion doses may rangefrom about 1 to 1000 μg/kg/minute of compound, admixed with apharmaceutical carrier over a period ranging from several minutes toseveral days.

For topical administration, the compounds may be mixed with apharmaceutical carrier at a concentration of about 0.1% to about 10% ofdrug to vehicle. Another mode of administering the compounds of theinvention may utilize a patch formulation to affect transdermaldelivery.

Compounds of the invention may alternatively be administered in methodsof this invention by inhalation, via the nasal or oral routes, e.g., ina spray formulation also containing a suitable carrier.

Schemes

The group PG represents a protecting group. One skilled in the art willselect the appropriate protecting group compatible with the desiredreactions. The protecting groups may be removed at a convenientsubsequent stage using methods known from the art. Alternatively, it maybe necessary to employ, in the place of the ultimately desiredsubstituent, a suitable group that may be carried through the reactionscheme and replaced as appropriate with the desired substituent. Suchcompounds, precursors, or prodrugs are also within the scope of theinvention. Examples of preferred protecting groups include; carbamates,benzyl and substituted benzyl groups. Especially preferred protectinggroups are tert-butyloxycarbonyl and benzyl.

Compound IA can be converted to compound IIA by reaction with Lawesson'sreagent, in a solvent such as THF, diethyl ether or DCM. This reactionmay be performed at room temperature or heated overnight at or near theboiling point of the solvent.

Compound IIA may be converted to amine IIIA by treatment with analkylating agent such as trimethyloxonium tetrafluoroborate or methyliodide in a solvent such as DCM or DMF, at a temperature of between roomtemperature and 40° C. for between 1 and 48 hours.

Compound IVA may be converted to compound VA by treatment with hydrazinemonohydrate in a solvent such as an alcohol, DCM or DMF at a temperaturenear room temperature for from 1 to 25 hours. Compound VIA may beconverted to compound VIIA by treatment with an appropriate acylatingagent such as oxalyl chloride in the presence of a catalyst such as DMFin a solvent such as DCM or DMF for from 1 to 8 hours. Compound VIIA maythen also be converted to compound VA by treatment with hydrazinemonohydrate in a solvent such as an alcohol, DCM or DMF at a temperaturenear room temperature for from 1 to 12 hours. Additionally compound VIABmay be converted to compound VIIAB by treatment with an appropriateacylating agent such as oxalyl chloride in the presence of a catalystsuch as DMF in a solvent such as DCM or DMF for from 1 to 8 hours. Ifcompounds of type IVA, VIA or VIAB are not commercially available, oneskilled in the art will realize there are numerous methods forsynthesizing these compounds. These may include hydrolysis of thecorresponding nitrile to afford VIA followed by esterification to giveIVA. The nitrile in turn can be obtained from a cross-coupling reactionwith a suitable halogen containing compound. Hydrolysis of thecorresponding nitrile to could also afford VIAB. Or VIA or VIAB can bedirectly formed from the halogen compound via metal halogen exchangefollowed by quenching with CO₂. VIA or VIAB can also be formed byoxidation of a suitable methyl substituted compound with a reagent, suchas, KMnO₄ and then IVA may be formed by subsequent esterification ofVIA. These compounds can also be formed by oxidation of an appropriatelysubstituted hydroxymethyl compound in either one or two steps to affordVIA or VIAB.

Compound IIIA may be converted to compound VIIIA by the addition ofcompound VA and a suitable base such as potassium t-butoxide in analcohol solvent such as methanol. This reaction can be performed at atemperature from room temperature to 120° C. for from 30 minutes to 48hours. Compound VIIIA can then be converted to compound IXA by additionof a suitable acid such as HCl or TFA, preferably TFA in a solvent suchas DCM, DCE or dioxane. This reaction can be performed at a temperaturefrom room temperature to 50° C. for from 30 minutes to 24 hours.

EXAMPLES

Exemplary compounds useful in methods of the invention will now bedescribed by reference to the illustrative synthetic schemes for theirgeneral preparation below and the specific examples that follow.Artisans will recognize that, to obtain the various compounds herein,starting materials may be suitably selected so that the ultimatelydesired substituents will be carried through the reaction scheme with orwithout protection as appropriate to yield the desired product.Alternatively, it may be necessary or desirable to employ, in the placeof the ultimately desired substituent, a suitable group that may becarried through the reaction scheme and replaced as appropriate with thedesired substituent. Unless otherwise specified, the variables are asdefined above in reference to Formula (I, IIa and IIb). Reactions may beperformed between the melting point and the reflux temperature of thesolvent, and preferably between 0° C. and the reflux temperature of thesolvent. Reactions may be heated employing conventional heating ormicrowave heating. Reactions may also be conducted in sealed pressurevessels above the normal reflux temperature of the solvent.

In obtaining the compounds described in the examples below and thecorresponding analytical data, the following experimental and analyticalprotocols were followed unless otherwise indicated.

Unless otherwise stated, reaction mixtures were magnetically stirred atroom temperature (rt) under a nitrogen atmosphere. Where solutions were“dried,” they were generally dried over a drying agent such as Na₂SO₄ orMgSO₄. Where mixtures, solutions, and extracts were “concentrated”, theywere typically concentrated on a rotary evaporator under reducedpressure. Reactions under microwave irradiation conditions were carriedout in a Biotage Initiator or CEM Corporation Discover instrument.Hydrogenations on the H-cube were run by passing solvent containingreactant through a catalyst cartridge on an H-Cube hydrogenationapparatus at a pressure of 15 to 100 bar and a flow rate of 1 to 30ml/min.

Normal-phase silica gel column chromatography (sgc) was performed onsilica gel (SiO₂) using prepackaged cartridges, eluting with 2 MNH₃/MeOH in CH₂Cl₂ unless otherwise indicated.

Preparative reverse-phase high performance liquid chromatography (HPLC)was performed on a Agilent HPLC with an Xterra Prep RID₁₈ (5 μm, 30×100mm, or 50×150 mm) column, and a gradient of 10 to 99% acetonitrile/water(20 mM NH₄OH) over 12 to 18 min, and a flow rate of 30 or 80 mL/min,unless otherwise indicated.

Mass spectra (MS) were obtained on an Agilent series 1100 MSD usingelectrospray ionization (ESI) in positive mode unless otherwiseindicated. Calculated (calcd.) mass corresponds to the exact mass.

Nuclear magnetic resonance (NMR) spectra were obtained on Bruker modelDRX spectrometers. The format of the ¹H NMR data below is: chemicalshift in ppm downfield of the tetramethylsilane reference (multiplicity,coupling constant J in Hz, integration).

A notation of (±) or R/S indicates that the product is a racemic mixtureof enantiomers and/or diastereomers. A notation of, for example, (2S,3R) indicates that product stereochemistry depicted is based on theknown stereochemistry of similar compounds and/or reactions. A notationof, for example, (2S*, 3R*) indicates that the product is a pure andsingle diastereomer but the absolute stereochemistry is not establishedand relative stereochemistry is shown.

Chemical names were generated using Chem Draw Ultra 6.0.2 (CambridgeSoftCorp., Cambridge, Mass.).

Abbreviations and acronyms used herein include the following:

Term Acronym/Abbreviation Reverse Phase High-pressure liquid HPLC or RPHPLC chromatography Tetrahydrofuran THF tert-Butylcarbamoyl Boc, BOCDichloromethane DCM Trifluoroacetic acid TFA N,N-Dimethylformamide DMFMethanol MeOH Ethanol EtOH Isopropanol IPA, iPrOH n-butanol n-BuOHAcetonitrile ACN, MeCN Ethyl Acetate EtOAc, or EA Triethylamine TEA1-Ethyl-3-(3- EDCI dimethylaminopropyl)carbodiimide Dimethyl sulfoxideDMSO Hexane HEX Supercritical fluid chromatography SFC Sodium AcetateNaOAc Room Temperature RT, rt

Example 1(2,3-dichlorophenyl)(8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 1 Step a: tert-Butyl 2-methyl-3-oxopiperazine-1-carboxylate

To 3-methylpiperazin-2-one (1.08 g, 9.33 mmol) in 1:1 THF/H₂O (45 mL)was added Na₂CO₃ (2.08 g, 19.60 mmol) and BOC-anhydride (2.24 g, 10.27mmol). The reaction was allowed to stir for 4 h, then extracted withDCM. The combined organics were washed 1× with brine, dried over Na₂SO₄,filtered and concentrated in vacuo (2.00 g, 99%). MS (ESI) mass calcd.C₁₀H₁₈N₂O₃, 214.13; m/z found 429.0 [2M+H]⁺, 159.0 [M+H-tBu]⁺. 1H NMR(500 MHz, CDCl₃): 8.05 (s, 1H), 4.42 (s, 2H), 3.69-3.61 (m, 2H), 2.63(s, 2H), 1.49 (s, 9H).

Example 1 Step b: tert-Butyl8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate

To a solution of the product of Example 1, step a (230 mg, 1.08 mmol) inDCM (5 mL) was added trimethyloxonium tetrafluoroborate (194 mg, 1.25mmol). The reagent slowly dissolved and after stirring overnight all ofthe starting material was consumed. To this solution was added2-picolinyl hydrazide (181 mg, 1.29 mmol). After 24 h the reaction wasconcentrated in vacuo and dissolved in dioxane (2 mL) and saturatedaqueous NaHCO₃ solution (2 mL). The mixture was heated for 3 h at 90° C.and the dioxane was removed in vacuo and the aqueous layer extractedwith DCM and EtOAc. The combined organic extracts were dried over Na₂SO₄filtered and concentrated in vacuo. Chromatography on SiO₂ eluting withIPA/EtOAc afforded the title compound (150 mg, 44%). MS (ESI) masscalcd. C₁₆H₂₁N₅O₂, 315.17; m/z found 316.0 [M+H]⁻.

Example 1 Step c:8-methyl-3-(pyridin-2-yl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine

To the product of Example 1, step b (150 mg, 0.48 mmol) in DCM (2 mL)was added TFA (0.48 mL). After stirring 3 h, the reaction wasconcentrated in vacuo. The residue was redissolved in DCM and treatedwith Dowex 550A resin. The resin was removed by filtration andconcentration afforded a white solid. Chromatography on SiO₂ elutingwith 2M NH₃ in MeOH/DCM afforded the desired compound (100 mg, 98%). MS(ESI) mass calcd. C₁₁H₁₃N₅, 215.12; m/z found 216.0 [M+H]⁺.

Example 1 Step d:7-[(2,3-Dichlorophenyl)carbonyl]-8-methyl-3-pyridin-2-yl-5,6,7,8-tetrahydro[1,2,4]triazolo[4,3-a]pyrazine

To a solution of the product of Example 1, step c (83 mg, 0.39 mmol) inDCM (4 mL) was added 2,4-dichlorobenzoic acid (74 mg, 0.39 mmol)followed by EDCI (111 mg, 0.58 mmol), HOBt (36 mg, 0.27 mmol) and TEA(0.11 mL, 0.77 mmol). The mixture was stirred overnight and then loadeddirectly on a column. Chromatography on SiO₂ eluting with EtOAc/Hexafforded impure material. Purification of this material on a PrepAgilent system with a XBridge C18 OBD 50×100 mm column eluting with 5 to99% 0.05% NH₄OH in H₂O/ACN over 17 min afforded the desired product (51mg, 34%). MS (ESI) mass calcd. C₁₈H₁₅Cl₂N₅O, 387.07; m/z found 387.9[M+H]⁺. 1H NMR (500 MHz, CDCl3): 8.68-8.52 (m, 1H), 8.38-8.28 (m, 1H),7.88-7.80 (m, 1H), 7.60-7.53 (m, 1H), 7.39-7.27 (m, 3H), 6.24-6.17 (m,0.5H), 5.22-4.91 (m, 2H), 4.44-4.10 (m, 1H), 3.73-3.32 (m, 1.5H),1.84-1.57 (m, 3H).

Example 2(R)-(2,3-dichlorophenyl)(8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 2, absolute configuration unknown, was obtained by chiralseparation of Example 1 utilizing SFC.

Stationary Phase: Amycoat 5 μm 250×30 mm (L×I.D.) at 40° C.

Mobile Phase: 25.5 mL/min EtOH with 0.2% isopropylamine, 59.5 mL/min CO₂

Detection: UV 254 nm.

Example 2 was the second compound off the column (16 mg). MS (ESI) masscalcd. C₁₈H₁₅Cl₂N₅O, 387.07; m/z found 388.1 [M+H]⁺. 1H NMR (500 MHz,CDCl3): 8.67-8.53 (m, 1H), 8.37-8.29 (m, 1H), 7.87-7.80 (m, 1H),7.59-7.54 (m, 1H), 7.38-7.23 (m, 3H), 6.24-6.17 (m, 0.5H), 5.23-4.89 (m,2H), 4.43-4.10 (m, 1H), 3.74-3.61 (m, 1H), 3.59-3.32 (m, 0.5H),1.85-1.55 (m, 3H).

Example 3(S)-(2,3-dichlorophenyl)(8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 3, absolute configuration unknown, was obtained by chiralseparation of Example 1 utilizing SFC.

Stationary Phase: Amycoat 5 μm 250×30 mm (L×I.D.) at 40° C.

Mobile Phase: 25.5 mL/min EtOH with 0.2% isopropylamine, 59.5 mL/min CO₂

Detection: UV 254 nm.

Example 3 was the first compound off the column (16 mg). MS (ESI) masscalcd. C₁₈H₁₅Cl₂N₅O, 387.07; m/z found 388.1 [M+H]⁺. 1H NMR (500 MHz,CDCl3): 8.68-8.53 (m, 1H), 8.37-8.29 (m, 1H), 7.88-7.81 (m, 1H),7.60-7.54 (m, 1H), 7.38-7.23 (m, 3H), 6.23-6.17 (m, 0.5H), 5.22-4.91 (m,2H), 4.43-4.10 (m, 1H), 3.73-3.63 (m, 1H), 3.59-3.32 (m, 0.5H),1.84-1.52 (m, 3H).

Examples 4-11 can be made in a manner analogous to Example 1,substituting the appropriate starting materials for each step.

Example 4(2-chloro-3-(trifluoromethyl)phenyl)(5-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 5(2,3-dichlorophenyl)(5-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 6(2-chloro-3-(trifluoromethyl)phenyl)(3-(4-fluorophenyl)-5-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 7(2,3-dichlorophenyl)(3-(4-fluorophenyl)-5-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 8(2-chloro-3-(trifluoromethyl)phenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 9(2,3-dichlorophenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 10(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 11(2,3-dichlorophenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 12(R)-(2,3-dichlorophenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 12 was isolated following chiral SFC separation of Example 11 ona CHIRALCEL OD-H 5 μm 250×20mm column with mobile phase consisting of70% CO₂, 30% MeOH. Example 12 was the first eluting peak under theseconditions. MS (ESI): mass calcd. for C₁₉H₁₆Cl₂N₄O, 386.1; m/z found,386.10 [M+H]⁺.

Example 13(S)-(2,3-dichlorophenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 13 was isolated following chiral SFC separation of Example 11 ona CHIRALCEL OD-H 5 μm 250×20mm column with mobile phase consisting of70% CO₂, 30% MeOH. Example 13 was the second eluting peak under theseconditions. MS (ESI): mass calcd. for C₁₉H₁₆Cl₂N₄O, 386.1; m/z found,386.10 [M+H]⁺.

Example 14(R)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 14 was isolated following chiral SFC separation of Example 10 ona CHIRALCEL OD-H 5 μm 250×20mm column with mobile phase consisting of75% CO₂, 25% MeOH. Example 14 was the first eluting peak under theseconditions. MS (ESI): mass calcd. for C₂₀H₁₆ClF₃N₄O, 420.1; m/z found,420.10 [M+H]⁺.

Example 15(S)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 15 was isolated following chiral SFC separation of Example 10 ona CHIRALCEL OD-H 5 μm 250×20mm column with mobile phase consisting of75% CO₂, 25% MeOH. Example 14 was the second eluting peak under theseconditions. MS (ESI): mass calcd. for C₂₀H₁₆ClF₃N₄O, 420.1; m/z found,420.10 [M+H]⁺.

Example 16(3-chloro-2-(trifluoromethyl)pyridin-4-yl)(8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The title compound was prepared in a manner analogous to Example 1substituting 3-chloro-2-(trifluoromethyl)isonicotinic acid for2,3-dichlorobenzoic acid in Example 1, step d. MS (ESI) mass calcd.C₁₈H₁₄ClF₃N₆O, 422.09; m/z found 423.1 [M+H]⁺. 1H NMR (500 MHz, CDCl3):8.76-8.52 (m, 2H), 8.37-8.30 (m, 1H), 7.89-7.81 (m, 1H), 7.54-7.46 (m,1H), 7.41-7.30 (m, 1H), 6.23-6.15 (m, 1H), 5.25-4.91 (m, 2H), 4.43-4.08(m, 1H), 3.80-3.36 (m, 2H), 1.85-1.61 (m, 3H).

Example 17(2-chloro-3-(trifluoromethyl)phenyl)(8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The title compound was prepared in a manner analogous to Example 1substituting 2-chloro-3-(trifluoromethyl)benzoic acid for2,3-dichlorobenzoic acid in Example 1, step d. MS (ESI) mass calcd.C₁₉H₁₅ClF₃N₅O, 421.09; m/z found 422.1 [M+H]⁺. 1H NMR (500 MHz, CDCl3):8.67-8.51 (m, 1H), 8.37-8.29 (m, 1H), 7.88-7.79 (m, 2H), 7.59-7.30 (m,3H), 6.25-6.18 (m, 1H), 5.21-4.93 (m, 2H), 4.42-4.11 (m, 1H), 3.76-3.33(m, 1H), 1.85-1.58 (m, 3H).

Example 18(R)-(2,3-dichlorophenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

1H NMR (400 MHz, DMSO) δ 7.91-7.34 (m, 7H), 5.72-5.39 (m, 1H), 4.76-3.70(m, 4H), 1.27-0.96 (m, 3H). MS (ESI): mass calcd. for C₁₉H₁₅Cl₂FN₄O,404.1; m/z found, 405.1 [M+H]⁺.

Example 19(S)-(2,3-dichlorophenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

1H NMR (400 MHz, DMSO) δ 7.93-7.31 (m, 7H), 5.72-5.35 (m, 1H), 4.80-3.75(m, 4H), 1.23-0.96 (m, 3H). MS (ESI): mass calcd. for C₁₉H₁₅Cl₂FN₄O,404.1; m/z found, 405.1 [M+H]⁺.

Example 20(2-fluoro-3-(trifluoromethyl)phenyl)(8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The title compound was prepared in a manner analogous to Example 1substituting 2-fluoro-3-(trifluoromethyl)benzoic acid for2,3-dichlorobenzoic acid in Example 1, step d. MS (ESI) mass calcd.C₁₉H₁₅F₄N₅O, 405.12; m/z found 406.1 [M+H]⁺. 1H NMR (500 MHz, CDCl3):8.68-8.54 (m, 1H), 8.37-8.29 (m, 1H), 7.87-7.52 (m, 3H), 7.43-7.31 (m,2H), 6.19 (s, 1H), 5.22-4.96 (m, 2H), 4.43-4.17 (m, 1H), 3.85-3.37 (m,1H), 1.86-1.65 (m, 3H).

Example 21(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Intermediate 21A: (S)-tert-butyl (1-azidopropan-2-yl)carbamate

To a solution of Boc-L-alaninol (10.9 g, 61.7 mmol) in ether (300 mL) at0° C. was added triethylamine (12.8 mL, 92.5 mmol) followed bymethanesulonylchloride (4.8 mL, 61.7 mmol) and the reaction mixture wasstirred to 1 hour. Water was added and the resulting reaction mixturewas extracted with DCM. The organic layers were combined, dried,concentrated and the resulting residue was dissolved in DMF (100 mL). Tothe resulting solution was added sodium azide (8.0 g, 123.4 mmol) andthe reaction mixture was heated to 70° C. for 18 hours. The reactionmixture was cooled to rt, water was added and the reaction mixture wasextracted with EtOAc. The organic layers were combined, washed withbrine, dried, concentrated and purified by flash column chromatography(0-50% EtOAc in hexanes) to provide (S)-tert-butyl(1-azidopropan-2-yl)carbamate (8.5 g). 1H NMR (400 MHz, DMSO) δ7.05-6.84 (d, J=8.0 Hz, 1H), 3.72-3.55 (m, 1H), 3.26-3.19 (d, J=6.1 Hz,2H), 1.42-1.36 (s, 9H), 1.06-0.99 (d, J=6.8 Hz, 3H).

Intermediate 21B: (S)-tert-butyl(1-(2-chloroacetamido)propan-2-yl)carbamate

To a solution of (S)-tert-butyl (1-azidopropan-2-yl)carbamate (8.5g,42.4 mmol) in EtOAc (300 mL) was added 10% Pd/C (4.5g) and the reactionmixture was placed under H₂ atmosphere (60 psi) for 2 hours. Thereaction mixture was filtered through a pad of celite, concentrated andthe resulting residue was taken up in DCM (300 mL). The resultingsolution was cooled to −78° C. and triethylamine (8.9 mL) was addedfollowed by chloroacetyl chloride (3.5 mL, 44.6 mmol). The reactionmixture was stirred at −78° C. for 20 minutes then warmed to 0° C. whereit was stirred for 1 hour. Water was added and the resulting reactionmixture was extracted with DCM. The organic layers were combined, washedwith brine, dried, concentrated and purified by flash columnchromatography (0-100% EtOAc in hexanes) to provide (S)-tert-butyl(1-(2-chloroacetamido)propan-2-yl)carbamate (7.3 g). 1H NMR (400 MHz,DMSO) δ 8.28-8.10 (s, 1H), 6.79-6.60 (d, J=8.2 Hz, 1H), 4.16-3.97 (s,2H), 3.64-3.48 (m, 1H), 3.13-2.99 (m, 2H), 1.44-1.30 (s, 9H), 1.05-0.91(d, J=6.7 Hz, 3H).

Intermediate 21C: (S)-tert-butyl 2-methyl-5-oxopiperazine-1-carboxylate

(S)-Tert-butyl (1-(2-chloroacetamido)propan-2-yl)carbamate (7.3 g, 29.1mmol) was dissolved in trifluoroacetic acid (20 mL) and stirred at rtfor 15 minutes. The reaction mixture was concentrated and the resultingresidue was dissolved in THF (100 mL). To the resulting solution wasadded K₂CO₃ (20.1 g, 145.6 mmol) and the reaction mixture refluxed for20 hours. The reaction mixture was cooled to 60° C. and catalytic DMAPwas added followed by BOC-anhydride (12.5 mL, 58.2 mmol). The reactionmixture was stirred for 12 hours, water was added and the resultingreaction mixture was extracted with EtOAc. The organic layers werecombined, dried, concentrated and purified by flash columnchromatography (0-50% iPrOH in EtOAc) to provide (S)-tert-butyl2-methyl-5-oxopiperazine-1-carboxylate (4.6g). 1H NMR (400 MHz, DMSO) δ8.08-7.90 (s, 1H), 4.31-4.09 (s, 1H), 4.00-3.87 (d, J=17.9 Hz, 1H),3.63-3.51 (d, J=17.8 Hz, 1H), 3.37-3.33 (m, 1H), 3.04-2.93 (ddd, J=12.7,4.9, 2.5 Hz, 1H), 1.46-1.35 (s, 9H), 1.15-1.06 (d, J=6.7 Hz, 3H).

Intermediate 21D: (S)-tert-butyl3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate

To a solution of (S)-tert-butyl 2-methyl-5-oxopiperazine-1-carboxylate(1.3 g, 6.1 mmol) in DCM (31 mL) was added trimethyloxoniumtetrafluoroborate (1.0 g, 6.8 mmol) and the reaction mixture was stirredat rt for 6 hours. 4-fluorobenzohydrazide (1.2 g, 8.0 mmol) was addedand the reaction mixture was allowed to stir at rt overnight. Thereaction mixture was concentrated via gentle N₂ stream and the resultingresidue was dissolved in dioxane (15 mL). To the resulting solution wasadded saturated aqueous sodium bicarbonate (15 mL) and the reactionmixture was refluxed for 12 hours. The reaction mixture was cooled tort, diluted with EtOAc, washed with water, dried, concentrated andpurified by flash column chromatography (0-10% MeOH in DCM) to provide(S)-tert-butyl3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate(1.2 g). MS (ESI) mass calcd. C₁₇H₂₁FN₄O₂, 332.4; m/z found, 333.2[M+H]⁺.

Intermediate 21 E:(S)-3-(4-fluorophenyl)-6-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine

(S)-Tert-butyl3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate(0.2 g, 0.6 mmol) was dissolved in trifluoroacetic acid and stirred atrt for 20 minutes. The reaction mixture was concentrated and theresulting residue was used without further purification.

To a solution of(S)-3-(4-fluorophenyl)-6-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine(90 mg, 0.387 mmol) and 2-chloro-3-(trifluoromethyl)benzoyl chloride(109 mg, 0.452 mmol) in DCM (10 mL) was added triethylamine (0.2 mL, 1.5mmol) and the reaction mixture was stirred at rt for 1 hour. Water wasadded and the resulting reaction mixture was extracted with DCM. Theorganic layers were combined, dried, concentrated and purified by flashcolumn chromatography (0-70% iPrOH in EtOAc) to provide(S)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-(pyrazin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(70 mg). 1H NMR (400 MHz, DMSO) δ 7.93-7.31 (m, 7H), 5.72-5.35 (m, 1H),4.80-3.75 (m, 4H), 1.23-0.96 (m, 3H). MS (ESI): mass calcd. forC₂₀H₁₅ClF₄N₄O, 438.1; m/z found, 439.1[M+H]⁺.

Example 22(S)-(2,3-dichlorophenyl)(6-methyl-3-(pyrazin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2,3-dichlorophenyl)(6-methyl-3-(pyrazin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in an analogous fashion to that described for(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewhere in 2,3-dichlorobenzoyl chloride was used in place of2-chloro-3-(trifluoromethyl)benzoyl chloride andpyrazine-2-carbohydrazide was used in place of 4-fluorobenzohydrazide.1H NMR (400 MHz, DMSO) δ 9.54-8.01 (m, 3H), 7.90-7.25 (m, 3H), 5.73-5.46(m, 1H), 4.90-4.02 (m, 3H), 3.85-3.57 (m, 1H), 1.34-0.98 (m, 3H). MS(ESI): mass calcd. for C₁₇H₁₄Cl₂N₆O, 388.1; m/z found, 390.1 [M+H]⁺.

Example 23(S)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-(pyrazin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-(pyrazin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in an analogous manor to(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewhere in pyrazine-2-carbohydrazide was used in place of4-fluorobenzohydrazide. 1H NMR (400 MHz, DMSO) δ 9.51-8.68 (m, 3H),8.22-7.45 (m, 3H), 5.75-5.24 (m, 1H), 4.91-4.05 (m, 3H), 3.92-3.57 (m,1H), 1.37-0.98 (m, 3H). MS (ESI): mass calcd. for C₁₈H₁₄ClF₃N₆O, 422.1;m/z found, 423.1 [M+H]⁺.

Example 24(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(furan-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Intermediate 23A: (S)-tert-butyl6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate

Step A: (S)-tert-butyl6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate

(S)-tert-butyl6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylatewas prepared as described for Intermediate 21D, substituting formic acidhydrazide for 4-fluorobenzohydrazide. MS (ESI) mass calcd. C₁₁H₁₇BrN₄O₂,316.05; m/z found, 317.1 [M+H]⁺.

Intermediate 23B: (S)-tert-butyl3-bromo-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate

Step B: (S)-tert-butyl3-bromo-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate

To a solution of (S)-tert-butyl6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate(75 mg, 0.32 mmol) in chloroform (3 mL) was added N-bromosuccinimide (61mg, 0.35 mmol) and sodium bicarbonate (53 mg, 0.63 mmol). The solutionwas allowed to stir overnight at rt then saturated sodium bicarbonate (2mL was added). The layers were separated and the water layer wasextracted two times more with methylene chloride. The organic layerswere combined, dried over anhydrous MgSO₄, filtered and concentrated.The residue was purified by HPLC (Agilent prep system, Waters XBridgeC18 5 μm 50×100 mm column, 5-99% MeCN/20 nM NH₄OH over 18 min at 80mL/min) to provide the product (45 mg, 45%). MS (ESI) mass calcd.C₁₁H₁₇BrN₄O₂, 316.05; m/z found, 317.1 [M+H]⁺.

Intermediate 23C: (S)-tert-butyl3-(furan-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate

Step C: (S)-tert-butyl3-(furan-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate

To a solution of (S)-tert-butyl3-bromo-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate(44 mg, 0.14 mmol) in 1,4-dioxane (1 mL) was added 2-furanylboronic acid(47 mg, 0.42 mmol),[1,1′-BIS(DIPHENYLPHOSPHINO)FERROCENE]DICHLOROPALLADIUM(II) (15 mg,0.021 mmol), 1,1′-BIS(DIPHENYLPHOSPHINO)FERROCENE (5 mg, 0.008 mmol),and potassium phosphate (88 mg, 0.42 mmol). The flask was flushed withnitrogen, sealed and heated to 100° C. overnight. The reaction wasallowed to cool and then filtered through celite. The filtrate wasconcentrated and the residue was purified by silica gel chromatography(30-100% ethyl acetate/hexanes) to provide the product (30 mg, 71%). MS(ESI) mass calcd. C₁₅H₂₀N₄O₃, 304.15; m/z found, 305.2 [M+H]⁺.

Example 24(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(furan-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Step D:(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(furan-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

To a solution of (S)-tert-butyl3-(furan-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate(30 mg, 0.1 mmol) in CH₂Cl₂ (1 mL) was added TFA (0.15 mL, 2.0 mmol).The reaction was allowed to stir at rt for 3 h and then evaporated invacuo. The residue was dissolved in CH₂Cl₂ (5 mL) and cooled to 0° C.after which was added triethylamine (0.092 mL, 0.66 mmol) and (64 mg,0.26 mmol). The ice bath was removed and warmed to rt followed by theaddition of water (5 mL). The layers were separated and the water layerwas extracted with CH₂Cl₂ two times more. The organic layers werecombined, dried with MgSO4 and purified by prep HPLC (Agilent prepsystem, Waters XBridge C18 5 μm 50×100 mm column, 5-99% MeCN/20 nM NH₄OHover 18 min at 80 mL/min) to provide the product (42 mg, 77%). MS (ESI):mass calcd. for C₁₈H₁₄ClF₃N₄O₂, 410.1; m/z found, 411.1 [M+H]⁺.

Example 25(2-chloro-3-(trifluoromethyl)phenyl)(3-(4-fluorophenyl)-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 25 Step a: tert-butyl 2-methyl-3-thioxopiperazine-1-carboxylate

To a heterogeneous mixture of Lawesson's reagent (2.11 g, 5.06 mmol) intoluene (18 mL) was added the product of Example 1, step a (1.01 g, 4.73mmol). The mixture was heated at 80° C. for 1 h and then concentrated invacuo. The residue was dissolved in DCM and filter loaded on SiO₂ columneluting with EtOAc/Hex to afford the desired product as an orange solid(1.12 g, 100%). MS (ESI) mass calcd. C₁₀H₁₈N₂O₂S, 230.11; m/z found231.1 [M+H]⁺. 1H NMR (500 MHz, CDCl3): 8.39 (s, 1H), 5.27-4.84 (m, 1H),4.30-3.92 (m, 1H), 3.53-3.42 (m, 1H), 3.39-3.30 (m, 1H), 3.30-3.05 (m,1H), 1.62 (d, J=7.0 Hz, 3H), 1.48 (s, 9H).

Example 25 Step b: tert-butyl3-(4-fluorophenyl)-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate

The product of Example 25, step a (230 mg, 1.00 mmol) and4-fluorobenzhydrazide (241 mg, 1.50 mmol) were added to a round bottomflask followed by n-BuOH (4 mL). The mixture was heated at 140° C. for48 h. The mixture was concentrated in vacuo and taken on to the nextstep without further purification. MS (ESI) mass calcd. C₁₇H₂₁FN₄O₂,332.16; m/z found 333.2 [M+H]⁺.

Example 25 Step c:3-(4-fluorophenyl)-8-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine

To the product of Example 25, step b (332 mg, 1.00 mmol) in DCM (5 mL)was added TFA (2 mL). After stirring 2 h, the reaction was complete andconcentrated in vacuo. The TFA salt was loaded on SiO₂ column elutingwith 2 M NH₃ in MeOH/DCM over 1 h to afford the desired compound as apale yellow solid. MS (ESI) mass calcd. C₁₂H₁₃FN₄, 232.11; m/z found233.1 [M+H]⁺. 1H NMR (500 MHz, CDCl3): 7.71-7.65 (m, 2H), 7.23-7.16 (m,2H), 4.35-4.29 (m, 1H), 4.08-3.97 (m, 2H), 3.45-3.38 (m, 1H), 3.19-3.11(m, 1H), 1.69 (d, J=6.7 Hz, 3H).

Example 25 Step d:7-{[2-Chloro-3-(trifluoromethyl)phenyl]carbonyl}-3-(4-fluorophenyl)-8-methyl-5,6,7,8-tetrahydro[1,2,4]triazolo[4,3-a]pyrazine

To a solution of the product of Example 25, step c (189 mg, 0.82 mmol)in DCM (8 mL) was added TEA (0.14 mL, 0.98 mmol) followed by2-chloro-3-(trifluoromethyl)benzoyl chloride (208 mg, 0.86 mmol) in oneportion. The reaction was stirred overnight and then loaded directly ona SiO₂ column eluting with IPA/EtOAc to afford the title compound as acolorless solid (324 mg, 91%). MS (ESI) mass calcd. C₂₀H₁₅ClF₄N₄O,438.09; m/z found 439.1 [M+H]⁺. 1H NMR (500 MHz, CDCl3) d 7.86-7.80 (m,1H), 7.74-7.63 (m, 2H), 7.60-7.40 (m, 2H), 7.26-7.16 (m, 2H), 6.23-6.15(m, 1H), 5.20-4.97 (m, 1H), 4.34-3.95 (m, 2H), 3.73-3.25 (m, 1H),1.86-1.53 (m, 3H).

Example 26(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Intermediate 26A: (S)-tert-butyl2-methyl-5-thioxopiperazine-1-carboxylate

To a solution of (S)-tert-butyl 2-methyl-5-oxopiperazine-1-carboxylate(1.2 g, 5.6 mmol) in THF 20 mL) was added Lawesson's Reagent (2.6 g, 6.2mmol) and the reaction mixture was heated to 80° C. for 1 hour. Thereaction mixture was concentrated and purified by flash columnchrmotatography (0-50% EtOAc in hexanes) to provide (S)-tert-butyl2-methyl-5-thioxopiperazine-1-carboxylate with minor residualimpurities. 1H NMR (400 MHz, DMSO) δ 10.64-10.46 (s, 1H), 4.48-4.31 (d,J=18.9 Hz, 1H), 4.31-4.12 (s, 1H), 4.11-3.93 (m, 1H), 3.90-3.74 (m, 1H),3.20-3.06 (m, 1H), 1.48-1.35 (s, 9H), 1.09-1.02 (d, J=6.6 Hz, 3H).

Intermediate 26B: (S)-tert-butyl6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate

To a solution of (S)-tert-butyl2-methyl-5-thioxopiperazine-1-carboxylate (350 mg, 1.52 mmol) inn-butanol (3 mL) was added 4-(trifluoromethyl)benzohydrazide (479 mg,2.28 mmol) and the reaction mixture was heated to 140° C. for 48 hours.The reaction mixture was cooled to rt and diluted with methanol (10 ml).BOC-anhydride (0.65 mL, 3.04 mmol) was added and the reaction mixturewas stirred for 5 hours. The reaction mixture was diluted with EtOAc,washed with water, dried, concentrated and purified by flash columnchromatography (0-100% EtOAc in hexanes) to provide (S)-tert-butyl6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate(375 mg).

Intermediate 26C:(S)-6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine

(S)-tert-butyl6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylatewas dissolved in trifluoroacetic acid and stirred at rt for 10 minutes.The reaction mixture was concentrated to provide(S)-6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazinewhich was used without further purification.

To a solution of(S)-6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine(72 mg, 0.26 mmol) in DCM (5 mL) was added 2,3-dichlorobenzoyl chloride(107 mg, 0.51 mmol) and triethylamine (0.18 mL, 1.28 mmol) and thereaction mixture was stirred for 4 hours at rt. Water was added and thereaction mixture was extracted with DCM. The organic layers werecombined, dried, concentrated and purified by hplc. 1H NMR (400 MHz,DMSO) δ 8.18-7.38 (m, 7H), 5.78-5.17 (m, 1H), 4.81-3.81 (m, 4H),1.25-0.96 (m, 3H). MS (ESI): mass calcd. for C₂₀H₁₅Cl₂F₃N₄O, 454.1; m/zfound, 455.1 [M+H]⁺.

Example 27(S)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in an analogous manor to(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewhere in 2-chloro-3-(trifluoromethyl)benzoyl chloride was used in placeof 2,3-dichlorobenzoyl chloride. 1H NMR (400 MHz, DMSO) δ 8.12-7.59 (m,7H), 5.76-5.24 (m, 1H), 4.79-3.80 (m, 4H), 1.36-0.75 (m, 3H). MS (ESI):mass calcd. for C₂₁H₁₅ClF₆N₄O, 488.1; m/z found, 489.1 [M+H]⁺.

Example 28(S)-(2,3-dichlorophenyl)(3-(3-fluoro-4-(trifluoromethyl)phenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2,3-dichlorophenyl)(3-(3-fluoro-4-(trifluoromethyl)phenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in analogous fashion(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewhere in 3-fluoro-4-(trifluoromethyl)benzohydrazide was used in place of4-(trifluoromethyl)benzohydrazide. 1H NMR (400 MHz, DMSO) δ 8.07-7.37(m, 6H), 5.74-5.19 (m, 1H), 4.85-3.87 (m, 4H), 1.26-0.96 (m, 3H). MS(ESI): mass calcd. for C₂₀H₁₄Cl₂F₄N₄O, 472.0; m/z found, 473.1 [M+H]⁺.

Example 29(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(3-fluoro-4-(trifluoromethyl)phenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(3-fluoro-4-(trifluoromethyl)phenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in an analogous fashion to(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewherein3-fluoro-4-(trifluoromethyl)benzohydrazide was used in place of4-(trifluoromethyl)benzohydrazide and2-chloro-3-(trifluoromethyl)benzoyl chloride was used in place of2,3-dichlorobenzoyl chloride. 1H NMR (400 MHz, DMSO) δ 8.15-7.62 (m,6H), 5.73-5.26 (m, 1H), 4.83-3.86 (m, 4H), 1.30-0.97 (m, 3H). MS (ESI):mass calcd. for C₂₁H₁₄ClF₇N₄O, 506.1; m/z found, 507.1 [M+H]⁺.

Example 30(S)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-(3,4,5-trifluorophenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-(3,4,5-trifluorophenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in analogous fashion to(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewherein3,4,5-trifluorobenzohydrazide was used in place of4-(trifluoromethyl)benzohydrazide and2-chloro-3-(trifluoromethyl)benzoyl chloride was used in place of2,3-dichlorobenzoyl chloride. 1H NMR (400 MHz, DMSO) δ 8.08-7.59 (m,5H), 5.67-5.21 (m, 1H), 4.79-3.84 (m, 4H), 1.23-0.94 (m, 3H). MS (ESI):mass calcd. for C₂₀H₁₃ClF₆N₄O, 474.1; m/z found, 475.1 [M+H]⁺.

Example 31(S)-(2,3-dichlorophenyl)(6-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2,3-dichlorophenyl)(6-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in an analogous manor to that describe for(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewhere in picolinohydrazide was used in place of4-(trifluoromethyl)benzohydrazide. 1H NMR (400 MHz, DMSO) δ 8.83-7.41(m, 7H), 5.68-5.24 (m, 1H), 5.03-3.91 (m, 4H), 1.43-0.96 (m, 3H). MS(ESI): mass calcd. for C₁₈H₁₅Cl₂N₅O, 387.1; m/z found, 388.1[M+H]⁺.

Example 33(S)-(2,3-dichlorophenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 34(2,3-dichlorophenyl)(5-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 35(2-chloro-3-(trifluoromethyl)phenyl)(8-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The title compound was prepared in a manner analogous to Example 25substituting 4-(trifluoromethyl)benzhydrazide for 4-fluorobenzhydrazidein Example 25, step b. MS (ESI) mass calcd. C₂₁H₁₅ClF₆N₄O, 488.08; m/zfound 489.1 [M+H]⁺. 1H NMR (500 MHz, CDCl3): 7.89-7.74 (m, 5H),7.60-7.41 (m, 2H), 6.24-6.18 (m, 1H), 5.21-5.00 (m, 1H), 4.36-4.16 (m,1H), 4.08-4.00 (m, 1H), 3.73-3.64 (m, 1H), 3.56-3.28 (m, 1H), 1.86-1.61(m, 3H).

Example 36(2-chloro-3-(trifluoromethyl)phenyl)(8-methyl-3-(pyrazin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The title compound was prepared in a manner analogous to Example 25substituting pyrazine-2-carbohydrazide for 4-fluorobenzhydrazide inExample 25, step b. MS (ESI) mass calcd. C₁₈H₁₄ClF₃N₆O, 422.09; m/zfound 423.1 [M+H]⁺. 1H NMR (500 MHz, CDCl3): 9.63-9.55 (m, 1H),8.68-8.48 (m, 2H), 7.85-7.77 (m, 1H), 7.60-7.36 (m, 2H), 6.27-6.21 (m,1H), 5.21-4.83 (m, 2H), 4.43-4.09 (m, 1H), 3.78-3.35 (m, 1H), 1.86-1.57(m, 3H).

Example 37(2-chloro-3-(trifluoromethyl)phenyl)(3-(4-chlorophenyl)-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The title compound was prepared in a manner analogous to Example 25substituting 4-chlorobenzhydrazide for 4-fluorobenzhydrazide in Example25, step b. MS (ESI) mass calcd. C₂₀H₁₅Cl₂F₃N₄O, 454.06; m/z found 455.1[M+H]⁺. 1H NMR (500 MHz, CDCl3): 7.86-7.81 (m, 1H), 7.69-7.45 (m, 6H),6.21-6.16 (m, 1H), 5.19-4.98 (m, 1H), 4.31-3.97 (m, 2H), 3.72-3.26 (m,1H), 1.85-1.60 (m, 3H).

Example 38(S)-(2,3-dichlorophenyl)(3-(2-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2,3-dichlorophenyl)(3-(2-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in an analogous manor to(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewhere in 2-fluorobenzohydrazide was used in place of4-(trifluoromethyl)benzohydrazide. 1H NMR (400 MHz, DMSO) δ 7.90-7.32(m, 7H), 5.65-5.20 (m, 1H), 4.85-3.62 (m, 4H), 1.30-0.91 (m, 3H). MS(ESI): mass calcd. for C₁₉H₁₅Cl₂FN₄O, 404.1; m/z found, 405.1 [M+H]⁺.

Example 39(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(2-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(2-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in an analogous manor to(S(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewhere in 2-fluorobenzohydrazide was used in place of4-(trifluoromethyl)benzohydrazide and2-chloro-3-(trifluoromethyl)benzoyl chloride was used in place of2,3-dichlorobenzoyl chloride. 1H NMR (400 MHz, DMSO) δ 8.10-7.25 (m,7H), 5.68-5.19 (m, 1H), 4.86-3.58 (m, 4H), 1.28-0.86 (m, 3H). MS (ESI):mass calcd. for C₂₀H₁₅ClF₄N₄O, 438.1; m/z found, 439.1 [M+H]⁺.

Example 40(S)-(2,3-dichloro-4-fluorophenyl)(3-(2-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2,3-dichloro-4-fluorophenyl)(3-(2-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in an analogous fashion to(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewhere in 2-fluorobenzohydrazide was used in place of4-(trifluoromethyl)benzohydrazide and 2,3-dichloro-4-fluorobenzoylchloride was used in place of 2,3-dichlorobenzoyl chloride. 1H NMR (400MHz, DMSO) δ 7.98-7.28 (m, 7H), 5.69-5.01 (m, 1H), 4.78-3.54 (m, 4H),1.27-0.90 (m, 3H). MS (ESI): mass calcd. for C₁₉H₁₄Cl₂F₂N₄O, 422.1; m/zfound, 423.1[M+H]⁺.

Example 41(S)-(2,3-dichlorophenyl)(3-(3-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2,3-dichlorophenyl)(3-(3-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in an analogous manor to(S)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewherein 3-fluorobenzohydrazide was used in place of4-(trifluoromethyl)benzohydrazidec. 1H NMR (500 MHz, DMSO) δ 7.94-7.28(m, 7H), 5.74-5.19 (m, 1H), 4.82-3.76 (m, 4H), 1.30-0.84 (m, 3H). MS(ESI): mass calcd. for C₁₉H₁₅Cl₂FN₄O, 404.1; m/z found, 405.1 [M+H]⁺.

Example 42(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(3-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(3-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in an analogous manor to(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewherein 3-fluorobenzohydrazide was used in place of4-(trifluoromethyl)benzohydrazide and2-chloro-3-(trifluoromethyl)benzoyl chloride was used in place of2,3-dichlorobenzoyl chloride. 1H NMR (400 MHz, DMSO) δ 8.14-7.28 (m,7H), 5.73-5.19 (m, 1H), 4.90-3.80 (m, 4H), 1.42-0.90 (m, 3H). MS (ESI):mass calcd. for C₂₀H₁₅ClF₄N₄O, 438.1; m/z found, 439.1 [M+H]⁺.

Example 43(S)-(2,3-dichloro-4-fluorophenyl)(3-(3-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2,3-dichloro-4-fluorophenyl)(3-(3-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in an analogous manor to(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewherein 3-fluorobenzohydrazide was used in place of4-(trifluoromethyl)benzohydrazide. 1H NMR (400 MHz, DMSO) δ 7.96-7.23(m, 6H), 5.72-5.18 (m, 1H), 4.78-3.75 (m, 4H), 1.30-0.89 (m, 3H). MS(ESI): mass calcd. for C₁₉H₁₄Cl₂F₂N₄O, 422.1; m/z found, 423.1 [M+H]⁺.

Example 44(S)-(2,3-dichlorophenyl)(3-(2,3-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2,3-dichlorophenyl)(3-(2,3-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in a manor analogous to that described for(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewhere in 2,3-difluorobenzohydrazide was used in place of4-(trifluoromethyl)benzohydrazide. 1H NMR (600 MHz, DMSO) δ 7.85-7.34(m, 6H), 5.71-5.20 (m, 1H), 4.83-3.66 (m, 4H), 1.30-0.90 (m, 3H). MS(ESI): mass calcd. for C₁₉H₁₄Cl₂F₂N₄O, 422.1; m/z found, 423.1 [M+H]⁺.

Example 45(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(2,3-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(2,3-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in an analogous manor to(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewherein 2,3-difluorobenzohydrazide was used in place of4-(trifluoromethyl)benzohydrazide and2-chloro-3-(trifluoromethyl)benzoyl chloride was used in place of2,3-dichlorobenzoyl chloride. 1H NMR (600 MHz, DMSO) δ 8.13-7.20 (m,6H), 5.73-5.18 (m, 1H), 4.85-3.53 (m, 4H), 1.35-0.87 (m, 3H). MS (ESI):mass calcd. for C₂₀H₁₄ClF₅N₄O, 456.1; m/z found, 457.1 [M+H]⁺.

Example 46(S)-(2,3-dichloro-4-fluorophenyl)(3-(2,3-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2,3-dichloro-4-fluorophenyl)(3-(2,3-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in an analogous manor to(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewhere in 2,3-difluorobenzohydrazide was used in place of4-(trifluoromethyl)benzohydrazide and 2,3-dichloro-4-fluorobenzoylchloride was used in place of 2,3-dichlorobenzoyl chloride. 1H NMR (600MHz, DMSO) δ 7.81-7.36 (m, 5H), 5.70-5.16 (m, 1H), 4.76-3.49 (m, 4H),1.25-0.88 (m, 3H). MS (ESI): mass calcd. for C₁₉H₁₃Cl₂F₃N₄O, 440.0; m/zfound, 441.1 [M+H]⁺.

Example 47(S)-(2,3-dichlorophenyl)(3-(3,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2,3-dichlorophenyl)(3-(3,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in a manor analogous to(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewhere in 3,4-difluorobenzohydrazide was used in place of4-(trifluoromethyl)benzohydrazide. 1H NMR (600 MHz, DMSO) δ 7.98-7.33(m, 6H), 5.72-5.23 (m, 1H), 4.78-3.73 (m, 4H), 1.29-0.94 (m, 3H). MS(ESI): mass calcd. for C₁₉H₁₄Cl₂F₂N₄O, 422.1; m/z found, 423.1 [M+H]⁺.

Example 48(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(3,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(3,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in an analogous manor to(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewherein 3,4-difluorobenzohydrazide was used in place of4-(trifluoromethyl)benzohydrazide and2-chloro-3-(trifluoromethyl)benzoyl chloride was used in place of2,3-dichlorobenzoyl chloride. 1H NMR (600 MHz, DMSO) δ 8.11-7.48 (m,6H), 5.75-5.23 (m, 1H), 4.80-3.81 (m, 4H), 1.29-0.96 (m, 3H). MS (ESI):mass calcd. for C₂₀H₁₄ClF₅N₄O, 456.1; m/z found, 457.1 [M+H]⁺.

Example 49(S)-(2,3-dichloro-4-fluorophenyl)(3-(3,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2,3-dichloro-4-fluorophenyl)(3-(3,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in a manor analogous to that described for(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewhere in 3,4-difluorobenzohydrazide was used in place of4-(trifluoromethyl)benzohydrazide and 2,3-dichloro-4-fluorobenzoylchloride was used in place of 2,3-dichlorobenzoyl chloride. 1H NMR (600MHz, DMSO) δ 8.05-7.39 (m, 5H), 5.73-5.18 (m, 1H), 4.80-3.77 (m, 4H),1.38-0.91 (m, 3H). MS (ESI): mass calcd. for C₁₉H₁₃Cl₂F₃N₄O, 440.0; m/zfound, 441.1 [M+H]⁺.

Example 50(S)-(2,3-dichlorophenyl)(3-(2,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2,3-dichlorophenyl)(3-(2,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in a manor analogous to(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewhere in 2,4-difluorobenzohydrazide was used in place of4-(trifluoromethyl)benzohydrazide. 1H NMR (600 MHz, DMSO) δ 7.88-7.26(m, 6H), 5.71-5.17 (m, 1H), 4.79-3.53 (m, 4H), 1.35-0.87 (m, 3H). MS(ESI): mass calcd. for C₁₉H₁₄Cl₂F₂N₄O, 422.1; m/z found, 423.1 [M+H]⁺.

Example 51(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(2,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(2,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in a manor analogous to that described for(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewherein 2,4-difluorobenzohydrazide was used in place of4-(trifluoromethyl)benzohydrazide and2-chloro-3-(trifluoromethyl)benzoyl chloride was used in place of2,3-dichlorobenzoyl chloride. 1H NMR (600 MHz, DMSO) δ 8.12-7.23 (m,6H), 5.68-5.20 (m, 1H), 4.81-3.58 (m, 4H), 1.27-0.89 (m, 3H). MS (ESI):mass calcd. for C₂₀H₁₄ClF₅N₄O, 456.1; m/z found, 457.1 [M+H]⁺.

Example 52(S)-(2,3-dichloro-4-fluorophenyl)(3-(2,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(S)-(2-chloro-4-fluoro-3-(trifluoromethyl)phenyl)(3-(2,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in a manor analogous to(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewherein 2,4-difluorobenzohydrazide was used in place of4-(trifluoromethyl)benzohydrazide and 2,3-dichloro-4-fluorobenzoylchloride was used in place of 2,3-dichlorobenzoyl chloride. 1H NMR (600MHz, DMSO) δ 7.88-7.22 (m, 5H), 5.66-5.19 (m, 1H), 4.74-3.60 (m, 4H),1.26-0.84 (m, 3H). MS (ESI): mass calcd. for C₁₉H₁₃Cl₂F₃N₄O, 440.0; m/zfound, 441.1 [M+H]⁺.

Example 53(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Intermediate 53A: tert-butyl(2-(2-bromo-2-phenylacetamido)ethyl)carbamate

Step A: tert-butyl (2-(2-bromo-2-phenylacetamido)ethyl)carbamate

A solution of tert-butyl N-(2-aminoethyl)carbamate (10 g, 59.29 mmol) in40 mL of DCM was cooled to −78° C. Triethylamine (16.48 mL, 118.59 mmol)and 2-bromo-2-phenylacetyl chloride (13.85 g, 59.29 mmol) weresubsequently added and the reaction mixture was stirred for 20 minutesthen warmed to 0° C. and stirred for 1 hour. The reaction mixture wasquenched with water and then extracted three times with DCM. Thecombined organic layers were washed with brine, dried with MgSO4 andconcentrated under reduced pressure. The resulting residue was purifiedvia silica gel chromatography (0-50% ethyl acetate/hexanes) to providethe desired product (15.09 g, 71%) as a white solid. ¹H NMR (500 MHz,CDCl₃) δ 7.51-7.28 (m, 5H), 5.43-5.31 (m, 1H), 4.89 (s, 2H), 3.58-3.16(m, 4H), 1.56-1.32 (m, 9H). MS (ESI) mass calcd. C₁₅H₂₁BrN₂O₃, 357.2;m/z found, 358.2 [M+H]⁺.

Intermediate 53B: N-(2-aminoethyl)-2-bromo-2-phenylacetamide

Step B: N-(2-aminoethyl)-2-bromo-2-phenylacetamide

To a solution of tert-butyl(2-(2-bromo-2-phenylacetamido)ethyl)carbamate (7.8 g, 21.75 mmol) in 30mL of DCM was added Trifluoroacetic acid (16.6 mL, 217.49 mmol). Theresulting reaction mixture was allowed to stir at room temperatureovernight. The reaction mixture was concentrated into a brown residueunder reduced pressure and then washed with conc. NaHCO3 solution andextracted three times with DCM. The combined organic layers were driedusing MgSO4, filtered and concentrated to provide the desired product(10.54 g, 99%). MS (ESI) mass calcd. C₁₀H₁₃BrN₂O, 257.2; m/z found,258.2 [M+H]⁺.

Intermediate 53C: tert-butyl 3-oxo-2-phenylpiperazine-1-carboxylate

Step C: tert-butyl 3-oxo-2-phenylpiperazine-1-carboxylate

To a solution of N-(2-aminoethyl)-2-bromo-2-phenylacetamide (19.28 g,43.74 mmol) in 430 mL of THF was added anhydrous K2CO3 (60.46 g, 437.46mmol). The resulting reaction mixture was refluxed at 65° C. overnight.Di-tert-butyldicarbonate (19.28 g, 87.49 mmol) was subsequently addedand the reaction mixture was refluxed at 65° C. for an additional 5hours. The resulting reaction mixture was cooled to room temperature anddiluted with ethyl acetate then washed with water. The organic layer waspartitioned, dried with MgSO4, filtered and concentrated into a residue.The resulting residue was purified via silica gel chromatography (0-30%Ethyl acetate/hexanes) to provide the desired product (9.54 g, 79%) as awhite solid. ¹H NMR (500 MHz, CDCl₃) δ 7.42-7.27 (m, 5H), 6.02-5.71 (m,1H), 4.15-4.06 (m, 1H), 3.80-3.69 (m, 1H), 3.69-3.61 (m, 1H), 3.42-3.30(m, 1H), 1.51 (s, 9H). MS (ESI) mass calcd. C₁₅H₂₀N₂O₃, 276.3; m/zfound, 277.2 [M+H]⁺.

Intermediate 53D: tert-butyl 2-phenyl-3-thioxopiperazine-1-carboxylate

Step D: tert-butyl 2-phenyl-3-thioxopiperazine-1-carboxylate

To a mixture of Lawesson's reagent (4.15 g, 9.95 mmol) in 125 mL oftoluene was added tert-butyl 3-oxo-2-phenylpiperazine-1-carboxylate (2.5g, 9.05 mmol) in a 5 mL solution of toluene. The resulting reactionmixture was heated at 110° C. for 3 hours in a sealed tube. The reactionwas worked up with 10% NaOH solution and extracted three times withethyl acetate. The combined organic layers were dried with MgSO4,filtered and concentrated into a residue. The resulting residue waspurified via silica gel chromatography (0-50% ethyl acetate/hexanes) toprovide the desired product (613.8 mg, 23%) as a crystalline orangesolid. ¹H NMR (500 MHz, CDCl₃) δ 9.67 (s, 1H), 7.51-7.41 (m, 2H),7.37-7.27 (m, 3H), 6.13 (s, 1H), 4.08-3.77 (m, 1H), 3.53-3.38 (m, 1H),3.38-3.26 (m, 2H), 1.50 (s, 9H). MS (ESI) mass calcd. C₁₅H₂₀N₂S0₂,292.4; m/z found, 293.2 [M+H]⁺.

Intermediate 53E: tert-butyl3-(methylthio)-2-phenyl-5,6-dihydropyrazine-1(2H)-carboxylate

Step E: tert-butyl3-(methylthio)-2-phenyl-5,6-dihydropyrazine-1(2H)-carboxylate

To a stirred solution of tert-butyl2-phenyl-3-thioxopiperazine-1-carboxylate (390 mg, 1.334 mmol)) in 3 mlof acetonitrile was added iodomethane (227 mg, 1.601 mmol). Theresulting reaction mixture was stirred at room temperature overnight andthen concentrated under reduced pressure to provide the desired product(407 mg, 99%). ¹H NMR (500 MHz, CDCl₃) δ 7.51-7.41 (m, 3H), 7.40-7.31(m, 2H), 6.17 (s, 1H), 4.25-4.08 (m, 2H), 4.06-3.90 (m, 1H), 3.50-3.37(m, 1H), 3.08 (s, 3H), 1.48 (s, 9H). MS (ESI) mass calcd. C₁₆H₂₂N₂SO₂,306.4; m/z found, 307.2 [M+H]⁺.

Intermediate 53F: tert-butyl3-methyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate

Step F: tert-butyl3-methyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate

To a round-bottom flask was added tert-butyl3-(methylthio)-2-phenyl-5,6-dihydropyrazine-1(2H)-carboxylate (606 mg,1.978 mmol), acetic hydrazide (1.48 g, 19.76 mmol) followed by 10 mL ofn-butanol. The resulting reaction mixture was heated to 155° and stirredfor 3 hours. The reaction mixture was cooled to room temperature anddi-tert-butyl dicarbonate (436 mg, 1.978 mmol) was added. The reactionmixture was subsequently stirred for 1 hour at room temperature thenisolated and concentrated down into a brown residue which was purifiedvia silica gel chromatography (0-10% 2M NH3/MeOH in DCM) to produce thedesired product (390 mg, 63%). ¹H NMR (400 MHz, CDCl₃) δ 7.40-7.20 (m,5H), 1.54-1.48 (m, 9H), 6.67 (s, 1H), 4.45 (s, 1H), 3.98-3.77 (m, 2H),3.32-3.16 (m, 1H), 2.44 (s, 3H). MS (ESI) mass calcd. C₁₇H₂₂N₄O₂, 315.3;m/z found, 316.2 [M+H]⁺.

Intermediate 53G:3-methyl-8-phenyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine

Step G:3-methyl-8-phenyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine

To a solution of3-methyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine-7(8H)-carboxylate(390 mg, 1.241 mmol)) in 5 mL of DCM was added Trifluoroacetic acid(0.390 mL, 5.096 mmol). The resulting reaction mixture was allowed tostir at room temperature overnight. The reaction mixture wasconcentrated into a brown residue under reduced pressure and then washedwith conc. NaHCO3 solution and extracted three times with DCM. Thecombined organic layers were dried using MgSO4, filtered andconcentrated to provide the desired product (120 mg, 45%). MS (ESI) masscalcd. C₁₂H₁₄N₄, 214.2; m/z found, 215.2 [M+H]⁺.

Example 53(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Step H:(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

To a solution of3-methyl-8-phenyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine (120mg, 0.560 mmol) in 5 mL of DCM was added triethylamine (0.234 mL, 1.68mmol). The resulting reaction mixture was stirred for 5 min at roomtemperature and then cooled to 0° C. 2-chloro-3-(trifluoromethyl)benzoylchloride (272 mg, 1.120 mmol) was subsequently added and the reactionwas stirred at 0° C. for 20 min. The reaction was quenched with waterand warmed to room temperature then extracted three times with DCM. Thecombined organic layers were dried using MgSO4 and concentrated into aresidue, which was purified via basic HPLC (Agilent prep system, WatersXBridge C18 5 μm 50×100 mm column, 5-95% MeCN/20 nM NH₄OH over 22 min at80 mL/min) to provide the racemic product (157 mg, 67%). ¹H NMR (500MHz, CDCl₃) δ 7.87-7.70 (m, 1H), 7.60-7.29 (m, 7H), 6.21-5.93; 5.21-5.01(m, 1H), 4.16-3.30 (m, 4H), 2.51-2.45 (m, 3H). MS (ESI): mass calcd. forC₂₀H₁₆ClF₃N₄O, 420.1; m/z found, 421.0 [M+H]⁺.

Example 54(S)-(2,3-dichlorophenyl)(3-(6-fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

To a solution of(S)-3-(6-fluoro-2-pyridyl)-6-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine(110 mg, 0.41 mmol) (prepared as described in Example 54, Intermediate54B, replacing 4-methoxy-pyridine-2-carboxylic acid hydrazide with6-fluoro-pyridine-2-carboxylic acid hydrazide in step for intermediate54A) and triethylamine (0.283 mL, 2.04 mmol) in CH₂Cl₂ (3 mL) was added2,3-dichlorobenzoyl chloride (128.1 mg, 0.61 mmol) at 0° C. The reactionmixture was slowly warmed to room temperature and stirred for 1 h. Thereaction mixture was quenched with water and extracted with CH₂Cl₂. Theorganic layers were separated, dried (Na₂SO₄), filtered and the solventconcentrated in vacuo. The crude compound was purified by columnchromatography (silica, MeOH in EtOAC 0:100 to 10:90), the desiredfractiones were collected, the solvent evaporated to give(S)-(2,3-dichlorophenyl)(3-(6-fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(100 mg, 60%) as a white foam. ¹H NMR (500 MHz, CDCl₃) δ ppm 1.22 (d,J=6.9 Hz, 0.90H), 1.36-1.41 (m, 1.05H), 1.43 (d, J=6.9 Hz, 1.05H),4.09-4.27 (m, 0.80H), 4.42-4.51 (m, 0.70H), 4.55-4.84 (m, 1.70H), 4.98(d, J=13.9 Hz, 0.30H), 5.04 (d, J=13.9 Hz, 0.50H), 5.54-5.63 (m, 0.50H),5.82 (d, J=18.5 Hz, 0.30H), 5.95 (d, J=18.2 Hz, 0.20H), 7.00 (ddd,J=15.4, 8.2, 2.5 Hz, 1H), 7.17-7.39 (m, 2H), 7.54-7.61 (m, 1H),7.91-8.00 (m, 1H), 8.20-8.31 (m, 1H). MS (ESI): mass calcd. ForC₁₈H₁₄Cl₂FN₅O, 405.1; m/z found, 406.04 [M+H]⁺, [α]=+84.4° (589 nm, c0.55 w/v %, DMF, 20° C.

Example 55(S)-(2,3-dichlorophenyl)(3-(4-methoxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Intermediate 55A: (S)-tert-butyl3-(4-methoxy-2-pyridyl)-6-methyl-6,8-dihydro-5H-[1,2,4]triazolo[4,3-a]pyrazine-7-carboxylate

To a solution of (S)-tert-butyl2-methyl-5-thioxo-piperazine-1-carboxylate (Intermediate 26A, 0.5 g,2.17 mmol) in ethanol (5 mL) was added 4-methoxy-pyridine-2-carboxylicacid hydrazide (435 mg, 2.61 mmol). The reaction mixture was heated at150° C. in a sealed tube for 12 hours in a Q-TUBE. The solvent was thenevaporated and the crude product purified by column chromatography(silica, MeOH in EtOAc 0:100 to 10:90). The desired fractions werecollected and the solvent was evaporated to afford (S)-tert-butyl3-(4-methoxy-2-pyridyl)-6-methyl-6,8-dihydro-5H-[1,2,4]triazolo[4,3-a]pyrazine-7-carboxylateas an off-white solid that was used for the next reaction step withoutfurther purification.

Intermediate 55B:(S)-3-(4-methoxy-2-pyridyl)-6-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine

Trifluoroacetic acid (2.5 mL, 32.67 mmol) was added to a mixture of(S)-tert-butyl3-(4-methoxy-2-pyridyl)-6-methyl-6,8-dihydro-5H-[1,2,4]triazolo[4,3-a]pyrazine-7-carboxylate(457 mg, 1.32 mmol) in CH₂Cl₂ (2.5 mL). The solution was stirred for 15min at room temperature and then the mixture was basified with aq. satNaHCO₃ and extracted with CH₂Cl₂. The organic layers were separated,dried (Na₂SO₄), filtered and the solvent concentrated in vacuo to yield(S)-3-(4-methoxy-2-pyridyl)-6-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine(121 mg, 37.3%) as an off-white solid.

Example 55(S)-(2,3-dichlorophenyl)(3-(4-methoxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

2,3-Dichlorobenzoyl chloride (103.3 mg, 0.49 mmol) was added to astirred solution of(S)-3-(4-methoxy-2-pyridyl)-6-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine(121 mg, 0.49 mmol) and triethylamine (0.171 mL, 1.23 mmol) in CH₂Cl₂under nitrogen at 0° C. The reaction mixture was slowly warmed to roomtemperature and stirred for 1 h. The reaction mixture was quenched withwater and extracted with CH₂Cl₂ (1.5 mL). The organic layers wereseparated, dried (Na₂SO₄), filtered and the solvent concentrated invacuo. The crude product was purified by column chromatography (silica,MeOH in EtOAc 0:100 to 10:90) and the desired fractions were collectedand the solvent evaporated. The residue was further purified by columnchromatography (silica, CH3CN in CH₂Cl₂ 0/100 to 100/0). The desiredfractions were collected and the solvent evaporated. The residue wastriturated with diisopropyl ether to yield(S)-(2,3-dichlorophenyl)(3-(4-methoxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(81 mg, 39.3%) as an off-white solid. ¹H NMR (400 MHz, CDCl₃) δ ppm 1.19(d, J=6.9 Hz, 0.90H), 1.37 (d, J=6.9 Hz, 0.60H), 1.38 (d, J=6.9 Hz,0.30H), 1.41 (d, J=7.2 Hz, 1.20H), 3.93 (s, 0.90H), 3.94 (s, 2.10H),4.05-4.17 (m, 0.50H), 4.21 (dd, J=13.5, 4.5 Hz, 0.20H), 4.38-4.49 (m,0.80H), 4.54-4.75 (m, 1.10H), 4.77 (d, J=17.1 Hz, 0.40H), 4.89 (d,J=13.6 Hz, 0.20H), 5.02-5.19 (m, 0.80H), 5.49-5.60 (m, 0.50H), 5.80 (d,J=18.3 Hz, 0.30H), 5.94 (d, J=18.3 Hz, 0.20H), 6.87 (ddd, J=12.5, 5.8,2.5 Hz, 1H), 7.17-7.39 (m, 2H), 7.54-7.60 (m, 1H), 7.83-7.91 (m, 1H),8.31-8.37 (m, 0.40H), 8.43 (d, J=5.8 Hz, 0.60H). MS (ESI): mass calcd.for C₁₉H₁₇Cl₂N₅O₂, 417.1; m/z found, 418.3[M+H]⁺. [α]=+62.4° (589 nm, c0.42 w/v %, DMF, 20° C.).

Example 56(2-chlorophenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 57(3,4-difluoro-2-methylphenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 58(2-chloro-4-fluorophenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 59(2,3-dichloropyridin-4-yl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Example 60(3-cyclohexyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2,3-dichlorophenyl)methanone

(R,S)-(3-cyclohexyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2,3-dichlorophenyl)methanonewas generated in a manor analogous to(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewhere in (R,S)-tert-butyl 2-methyl-3-thioxopiperazine-1-carboxylate wasused in place of (S)-tert-butyl2-methyl-5-thioxopiperazine-1-carboxylate and cyclohexanecarbohydrazidewas used in in place of 4-(trifluoromethyl)benzohydrazide. 1H NMR (600MHz, DMSO) δ 7.92-7.36 (m, 3H), 6.02-5.81 (m, 1H), 4.23-3.53 (m, 3H),2.95-2.75 (m, 1H), 2.06-1.16 (m, 14H). MS (ESI): mass calcd. forC₁₉H₂₂Cl₂N₄O, 392.1; m/z found, 393.2 [M+H]⁺.

Example 61(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclohexyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(R,S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclohexyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in a manor analogous to(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewhere in (R,S)-tert-butyl 2-methyl-3-thioxopiperazine-1-carboxylate wasused in place of (S)-tert-butyl2-methyl-5-thioxopiperazine-1-carboxylate and cyclohexanecarbohydrazidewas used in place of 4-(trifluoromethyl)benzohydrazide and2-chloro-3-(trifluoromethyl)benzoyl chloride was used in place of2,3-dichlorobenzoyl chloride. 1H NMR (600 MHz, DMSO) δ 8.10-7.57 (m,3H), 5.98-5.81 (m, 1H), 4.35-3.42 (m, 3H), 3.01-2.80 (m, 1H), 2.02-1.19(m, 14H). MS (ESI): mass calcd. for C₂₀H₂₂ClF₃N₄O, 426.1; m/z found,427.2 [M+H]⁺.

Example 62(3-cyclohexyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2,3-dichloro-4-fluorophenyl)methanone

(R,S)-(3-cyclohexyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2,3-dichloro-4-fluorophenyl)methanonewas generated in a manor analogous to that described for(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewherein (R,S)-tert-butyl 2-methyl-3-thioxopiperazine-1-carboxylate wasused in place of (S)-tert-butyl2-methyl-5-thioxopiperazine-1-carboxylate, cyclohexanecarbohydrazide wasused in place of 4-(trifluoromethyl)benzohydrazide and2,3-dichloro-4-fluorobenzoyl chloride was used in place of2,3-dichlorobenzoyl chloride. 1H NMR (600 MHz, DMSO) δ 7.98-7.40 (m,2H), 5.88-5.69 (d, J=6.7 Hz, 1H), 4.06-3.48 (m, 4H), 1.96-1.07 (m, 14H).MS (ESI): mass calcd. for C₁₉H₂₁Cl₂FN₄O, 410.1; m/z found,411.2 [M+H]⁺.

Example 63(3-cyclopropyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2,3-dichlorophenyl)methanone

(R,S)-(3-cyclopropyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2,3-dichlorophenyl)methanonewas generated in a manor analogous to that described for(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewherein (R,S)-tert-butyl 2-methyl-3-thioxopiperazine-1-carboxylate wasused in place of (S)-tert-butyl2-methyl-5-thioxopiperazine-1-carboxylate and cyclopropanecarbohydrazidewas used in place of 4-(trifluoromethyl)benzohydrazide. 1H NMR (600 MHz,DMSO) δ 7.89-7.31 (m, 3H), 5.94-5.79 (m, 1H), 4.93-2.96 (m, 4H),2.15-1.95 (m, 1H), 1.48-0.66 (m, 7H).

Example 64(3-cyclopropyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2,3-dichloro-4-fluorophenyl)methanone

(R,S)-(3-cyclopropyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2,3-dichloro-4-fluorophenyl)methanonewas generated in a manor analogous to(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewhere in (R,S)-tert-butyl 2-methyl-3-thioxopiperazine-1-carboxylate wasused in place of (S)-tert-butyl2-methyl-5-thioxopiperazine-1-carboxylate, cyclopropanecarbohydrazidewas used in place of 4-(trifluoromethyl)benzohydrazide and2,3-dichloro-4-fluorobenzoyl chloride was used in place of2,3-dichlorobenzoyl chloride. 1H NMR (600 MHz, CDCl3) δ 12.48-12.11 (m,2H), 10.61-10.45 (d, J=6.8 Hz, 1H), 9.53-8.35 (m, 4H), 6.81-6.64 (m,1H), 6.44-5.46 (m, 7H).

Example 65(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclopropyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

(R,S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclopropyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewas generated in a manor analogous to(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonewhere in (R,S)-tert-butyl 2-methyl-3-thioxopiperazine-1-carboxylate wasused in place of (S)-tert-butyl2-methyl-5-thioxopiperazine-1-carboxylate, cyclopropanecarbohydrazidewas used in place of 4-(trifluoromethyl)benzohydrazide and2-chloro-3-(trifluoromethyl)benzoyl chloride was used in place of2,3-dichlorobenzoyl chloride. 1H NMR (600 MHz, DMSO) δ 8.08-7.54 (m,3H), 5.94-5.74 (m, 1H), 4.97-2.99 (m, 4H), 2.16-1.91 (m, 1H), 1.69-0.81(m, 7H).

Example 66(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 53.The racemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 65% CO₂, 35% iPrOH)yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ 7.86-7.73 (m,1H), 7.58-7.28 (m, 7H), 6.16-5.99; 5.21-5.05 (m, 1H), 4.16-3.31 (m, 4H),2.53-2.40 (m, 3H). MS (ESI) mass calcd. for C₂₀H₁₆ClF₃N₄O, 420.1; m/zfound, 421.0 [M+H]⁺.

Example 67(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 53.The racemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 65% CO₂, 35% iPrOH)yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ 7.84-7.74 (m,1H), 7.58-7.28 (m, 7H), 6.15-5.99; 5.19-5.05 (m, 1H), 4.17-3.31 (m, 4H),2.53-2.43 (m, 3H). MS (ESI) mass calcd. C₂₀H₁₆ClF₃N₄O, 420.1; m/z found,421.0 [M+H]⁺.

Example 68(S)-(2,3-dichlorophenyl)(3-(4-fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

To a solution of(S)-3-(4-iodopyridin-2-yl)-6-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine(30 mg, 0.088 mmol) (generated in a manor analogous to Intermediate 21Ewherein 4-iodopicolinohydrazide was used in place of4-fluorobenzhydrazide) in CH₂Cl₂ (1 mL) was added triethylamine (0.04mL, 0.3 mmol) and 2,3-dichlorobenzoyl chloride (24 mg, 0.11 mmol). Thereaction was allowed to stir at rt for 30 min and then evaporated invacuo. The residue was chromatographed (SiO₂, 0-10% 2 N NH₃inMeOH)/CH₂Cl₂). After concentration in vacuo the resulting residue wasdissolved in dry THF (0.2 mL) and tetrabutylammonium fluoride THFsolution (0.041 mL, 0.041 mmol) was added. The reaction was heated to120° C. for 5 min in the microwave. An additional 0.041 mmol TBAF wasadded and the reaction was heated in the microwave to 150° C. for 5 min,followed by 160° C. for 30 min and 165° C. for 40 min, and finally 160°C. for 90 min. The reaction was purified by prep HPLC (C18 XSelect19×100 5 μm, Mobile phase Gradient from 80% 0.1% NH₄CO₃H/NH₄OH pH 9solution in Water, 20% CH₃CN to 0% 0.1% NH₄CO₃H/NH₄OH pH 9 solution inWater, 100% CH₃CN) 1.6 mg, 9.6%). MS (ESI) mass calcd. C₁₈H₁₄Cl₂FN₅O,405.1; m/z found, 405.0.

Example 69(S)-(2,3-dichlorophenyl)(3-(5-fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

2,3-Dichlorobenzoyl chloride (94.3 mg, 0.45 mmol) was added to a stirredsolution of(S)-3-(5-fluoro-2-pyridyl)-6-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine(70 mg, 0.30 mmol) (prepared as described in Example 54, Intermediate54B, replacing 4-methoxy-pyridine-2-carboxylic acid hydrazide with5-fluoro-pyridine-2-carboxylic acid hydrazide in step for intermediate54A) and triethylamine (0.21 mL, 1.50 mmol) in CH₂Cl₂ (2 mL) undernitrogen at 0° C. The reaction mixture was slowly warmed to roomtemperature and stirred for 30 additional min. The reaction mixture wasquenched with water and extracted with CH₂Cl₂. The organic layers wereseparated, dried (Na₂SO₄), filtered and the solvent concentrated invacuo. The crude product was purified by column chromatography (silica,MeOH in EtOAc 0:100 to 10:90), the desired fractions were collected andthe solvent evaporated in vacuo to yield the desired compound with someimpurities. This was purified by RP HPLC on (C18 Sunfire 30×100 5 μm).Mobile phase (Gradient from 50% 0.1% NH₄CO₂CH₃ solution in Water, 40%CH₃CN to 40% 0.1% NH₄CO₂CH₃ solution in Water, 50% CH₃CN), yielding(S)-(2,3-dichlorophenyl)(3-(5-fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(31.3 mg, 24.4%).

MS (ESI) mass calcd. C₁₈H₁₄Cl₂FN₅O, 405.1; m/z found, 406.0 [M+H]⁺. ¹HNMR (500 MHz, CDCl₃) δ ppm 1.20 (d, J=6.6 Hz, 0.75H), 1.38 (d, J=6.9 Hz,0.75H), 1.38 (d, J=6.9 Hz, 0.45H), 1.42 (d, J=7.2 Hz, 1.05H), 4.07-4.18(m, 0.45H), 4.21 (dd, J=13.6, 4.6 Hz, 0.15H), 4.38-4.49 (m, 0.80H),4.53-4.83 (m, 1.80H), 4.92-5.06 (m, 0.85H), 5.52-5.61 (m, 0.55H), 5.81(d, J=18.5 Hz, 0.25H), 5.94 (d, J=18.2 Hz, 0.15H), 7.17-7.39 (m, 2H),7.54-7.60 (m, 2H), 8.34-8.44 (m, 1.30H), 8.50 (d, J=2.6 Hz, 0.70H).

Example 70(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(5-fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

2-Chloro-3-(trifluoromethyl)benzoyl chloride (159.4 mg, 0.66 mmol) wasadded to a stirred solution of(S)-3-(5-fluoro-2-pyridyl)-6-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine(102 mg, 0.44 mmol) and triethylamine (0.30 mL, 2.19 mmol) in CH₂Cl₂ (3mL) at 0° C. The reaction mixture was slowly warmed to room temperatureand stirred for 90 min. The reaction mixture was quenched with water andextracted with CH₂Cl₂. The organic layers were separated, dried(Na₂SO₄), filtered and the solvent concentrated in vacuo. The crudeproduct was purified by column chromatography (silica, MeOH in EtOAc0/100 to 10/90), the desired fractions were collected and the solventevaporated in vacuo. The product containing some impurities was purifiedby RP HPLC on (C18 Sunfire 30×100 5 μm). Mobile phase (Gradient from 60%0.1% NH₄CO₂CH₃ solution in Water, 40% CH₃CN to 40% 0.1% NH₄CO₂CH₃solution in Water, 60% CH₃CN), yielding(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(5-fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(0.27 g, 44.2%). MS (ESI) mass calcd. C₁₉H₁₄ClF₄N₅O, 439.1; m/z found,440.0 [M+H]⁺. ¹H NMR (400 MHz, CDCl₃) δ ppm 1.22 (d, J=6.9 Hz, 0.75H),1.39 (d, J=7.2 Hz, 0.45H), 1.40 (d, J=6.7 Hz, 0.60H), 1.43 (d, J=7.2 Hz,1.20H), 4.04-4.14 (m, 0.40H), 4.21 (dd, J=13.6, 4.6 Hz, 0.15H),4.39-4.49 (m, 0.85H), 4.56-4.85 (m, 1.80H), 4.93-5.09 (m, 0.85H),5.53-5.63 (m, 0.55H), 5.82 (d, J=18.3 Hz, 0.25H), 5.96 (d, J=18.3 Hz,0.15H), 7.45-7.61 (m, 3H), 7.79-7.86 (m, 1H), 8.33-8.44 (m, 1.40H), 8.51(d, J=2.8 Hz, 0.60H). [α]=+60.6° (589 nm, c 0.5 w/v %, DMF, 20° C.).

Example 71((S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(5-methoxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

2-Chloro-3-(trifluoromethyl)benzoyl chloride (127.8 mg, 0.526 mmol) wasadded to a stirred solution of(S)-3-(5-methoxy-2-pyridyl)-6-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine(86 mg, 0.35 mmol) (prepared as described in Example 54, Intermediate54B, replacing 4-methoxy-pyridine-2-carboxylic acid hydrazide with5-methoxy-pyridine-2-carboxylic acid hydrazide in step for intermediate54A) and triethylamine (0.24 mL, 1.75 mmol) in CH₂Cl₂ (3 mL) undernitrogen at 0° C. The reaction mixture was slowly warmed to roomtemperature and stirred for 30 min. The reaction mixture was quenchedwith water and extracted with CH₂Cl₂. The organic layers were separated,dried (Na₂SO₄), filtered and the solvent concentrated in vacuo. Thecrude product was purified twice by column chromatography (silica, MeOHin EtOAc 0:100 to 10:90), the desired fractions were collected and thesolvent evaporated in vacuo. Final purification was performed by RP HPLCon (C18 Sunfire 30×100 5 μm). Mobile phase (Gradient from 60% 0.1%NH₄CO₂CH₃ solution in Water, 40% CH₃CN to 40% 0.1% NH₄CO₂CH₃ solution inWater, 60% CH₃CN), yielding(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(5-methoxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(35.9 mg, 22.6%). MS (ESI) mass calcd. C₂₀H₁₇ClF₃N₅O₂, 451.1; m/z found,452.1[M+H]⁺. ¹H NMR (500 MHz, CDCl₃) δ ppm 1.20 (d, J=6.9 Hz, 0.75H),1.38 (dd, J=6.9, 2.0 Hz, 1.20H), 1.43 (d, J=7.2 Hz, 1.05H), 3.90-3.92(m, 1.30H), 3.93 (s, 1.70H), 4.01-4.12 (m, 0.40H), 4.19 (dd, J=13.6, 4.6Hz, 0.15 H), 4.37-4.47 (m, 0.85H), 4.54-4.90 (m, 1.85H), 4.95-5.11 (m,0.85H), 5.51-5.61 (m, 0.50H), 5.79 (d, J=18.2 Hz, 0.25H), 5.94 (d,J=18.2 Hz, 0.15H), 7.30-7.38 (m, 1H), 7.45-7.60 (m, 2H), 7.78-7.85 (m,1H), 8.20-8.35 (m, 2H).

Example 72(S)-(2,3-dichlorophenyl)(3-(5-methoxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to Example 71,using 2,3-dichlorobenzoyl chloride instead of2-chloro-3-(trifluoromethyl)benzoyl chloride. Further purification wasnot required. MS (ESI) mass calcd. C₁₉H₁₇Cl₂N₅O₂, 417.1; m/z found,418.0 [M+H]⁺. ¹H NMR (500 MHz, CDCl₃) δ ppm 1.19 (d, J=6.9 Hz, 0.75H),1.37 (d, J=6.6 Hz, 0.75H), 1.37 (d, J=6.9 Hz, 0.45H), 1.41 (d, J=6.9 Hz,1.05H), 3.89-3.92 (m, 1.20H), 3.93 (s, 1.80H), 4.04-4.16 (m, 0.40H),4.19 (dd, J=13.4, 4.8 Hz, 0.15H), 4.35-4.48 (m, 0.85H), 4.52-4.83 (m,1.85H), 4.93-5.09 (m, 0.85H), 5.48-5.60 (m, 0.50H), 5.78 (d, J=18.2 Hz,0.25H), 5.92 (d, J=18.2 Hz, 0.15H), 7.15-7.39 (m, 3H), 7.52-7.60 (m,1H), 8.19-8.36 (m, 2H).

Example 73(S)-(2,3-dichlorophenyl)(3-(5-fluoropyrimidin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

2,3-Dichlorobenzoyl chloride (60 mg, 0.29 mmol) was added to a stirredsolution of(S)-3-(5-fluoropyrimidin-2-yl)-6-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine(67 mg, 0.29 mmol) (prepared as described in Example 54, Intermediate54B, replacing 4-methoxy-pyridine-2-carboxylic acid hydrazide with5-fluoropyrimidine-2-carboxylic acid hydrazide in step for intermediate54A) and triethylamine (0.20 mL, 1.43 mmol) in CH₂Cl₂ (15 mL) undernitrogen at 0° C. The reaction mixture was slowly warmed to roomtemperature and stirred for 1 h. The reaction mixture was quenched withwater and extracted with CH₂Cl₂. The organic layers were separated,dried (Na₂SO₄), filtered and the solvent concentrated in vacuo. Thecrude product was purified by column chromatography (silica, MeOH inEtOAc 0:100 to 10:90), and the desired fractions were collected and thesolvent evaporated in vacuo to yield(S)-(2,3-dichlorophenyl)(3-(5-fluoropyrimidin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(45 mg, 38.5%). MS (ESI) mass calcd. C₁₇H₁₃Cl₂FN₆O, 406.1; m/z found,406.9 [M+H]⁺. ¹H NMR (400 MHz, CDCl₃) δ ppm 1.21 (d, J=6.7 Hz, 0.75H),1.38 (d, J=6.7 Hz, 0.60H), 1.39 (d, J=7.2 Hz, 0.60H), 1.43 (d, J=7.2 Hz,1.05H), 4.10-4.27 (m, 0.60H), 4.38-4.98 (m, 3.35H), 5.55-5.65 (m,0.60H), 5.85 (d, J=18.5 Hz, 0.25H), 5.97 (d, J=18.5 Hz, 0.20H),7.17-7.41 (m, 2H), 7.55-7.62 (m, 1H), 8.74 (s, 0.45H), 8.74 (s, 0.45H),8.78 (br s, 1H), M.P. 258.9° C. [α]=+56.8° (589 nm, c 0.48 w/v %, DMF,20° C.).

Example 74(S)-(2,3-dichlorophenyl)(3-(5-fluoropyrimidin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to Example 73,using 2-chloro-3-(trifluoromethyl)benzoyl chloride instead of2,3-dichlorobenzoyl chloride. MS (ESI) mass calcd. C₁₈H₁₃ClF₄N₆O, 440.1;m/z found, 441.0 [M+H]⁺. ¹H NMR (400 MHz, CDCl₃) δ ppm 1.22 (d, J=6.9Hz, 0.75H), 1.40 (dd, J=6.9, 1.2 Hz, 1.05H), 1.44 (d, J=6.9 Hz, 1.20H),4.06-4.19 (m, 0.55H), 4.23 (dd, J=13.5, 4.5 Hz, 0.15H), 4.39-4.53 (m,0.80H), 4.59-5.01 (m, 2.50H), 5.56-5.67 (m, 0.60H), 5.86 (d, J=18.7 Hz,0.25H), 5.99 (d, J=18.3 Hz, 0.15H), 7.46-7.60 (m, 2H), 7.80-7.87 (m,1H), 8.73 (s, 0.30H), 8.75 (s, 0.50H), 8.78 (s, 1.20H). M.P. >300° C.[α]=+51.0° (589 nm, c 0.44 w/v %, DMF, 20° C.).

Example 75(±)-(2-chloro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 108(using trifluoracetic anhydride instead of difluoroacetic anhydride inStep) and was purified via basic HPLC (Agilent prep system, WatersXBridge C18 5 um 50×100 mm column, 5-95% MeCN/20 nM NH₄OH over 22 min at80 mL/min) to provide the racemic product (6.8 mg, 25%). ¹H NMR (500MHz, CDCl₃) δ 7.87-7.75 (m, 1H), 7.61-7.29 (m, 7H), 6.25-6.08; 5.22-5.09(m, 1H), 4.39-3.35 (m, 4H). MS (ESI) mass calcd. C₂₀H₁₃ClF₆N₄O, 474.1;m/z found, 475.1 [M+H]⁺.

Example 76(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclopropyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 53(using cyclopropanecarbohydrazide instead of acetic hydrazide in StepF.) The racemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 70% CO₂, 30% iPrOH)yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ 7.86-7.71 (m,1H), 7.60-7.29 (m, 7H), 6.15-5.99; 5.20-5.02 (m, 1H), 4.25-3.30 (m, 4H),1.78-1.68 (m, 1H), 1.28-1.16 (m, 2H), 1.16-0.99 (m, 2H). MS (ESI) masscalcd. C₂₂H₁₈ClF₃N₄O, 446.1; m/z found, 447.1 [M+H]⁺.

Example 77(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclopropyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 53(using cyclopropanecarbohydrazide instead of acetic hydrazide in StepF.) The racemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 70% CO₂, 30% iPrOH)yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ 7.88-7.68 (m,1H), 7.60-7.29 (m, 7H), 6.19-5.93; 5.21-5.03 (m, 1H), 4.26-3.31 (m, 4H),1.79-1.67 (m, 1H), 1.28-1.16 (m, 2H), 1.16-1.02 (m, 2H). MS (ESI) masscalcd. C₂₂H₁₈ClF₃N₄O, 446.1; m/z found, 447.0 [M+H]⁺.

Example 78(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(5-methoxypyrimidin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to Example 74,replacing(S)-3-(5-fluoropyrimidin-2-yl)-6-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazinewith(S)-3-(5-methoxypyrimidin-2-yl)-6-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine.MS (ESI) mass calcd. C₁₉H₁₆ClF₃N₆O₂, 452.1; m/z found, 453.0 [M+H]⁺. ¹HNMR (400 MHz, CDCl₃) δ ppm 1.21 (d, J=6.9 Hz, 0.75H), 1.39 (d, J=7.4 Hz,0.45H), 1.39 (d, J=6.7 Hz, 0.60H), 1.43 (d, J=7.2 Hz, 1.20H), 3.99 (s,0.60H), 4.00 (s, 0.75H), 4.02 (s, 1.65H), 4.04-4.16 (m, 0.55H), 4.20(dd, J=13.8, 4.5 Hz, 0.15H), 4.37-4.50 (m, 0.80H), 4.57-5.03 (m, 2.50H),5.54-5.64 (m, 0.60H), 5.83 (d, J=18.5 Hz, 0.25H), 5.97 (d, J=18.3 Hz,0.15H), 7.45-7.60 (m, 2H), 7.78-7.88 (m, 1H), 8.50 (s, 0.30H), 8.52 (s,0.50H), 8.55 (s, 1.20H). M.P. 129.4° C.

Example 79(±)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(furan-2-yl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 53(using oxazole-2-carbohydrazide instead of acetic hydrazide in Step F.)¹H NMR (500 MHz, CDCl₃) δ 7.86-7.71 (m, 1H), 7.63-7.59 (m, 1H),7.57-7.28 (m, 7H), 7.21-7.13 (m, 1H), 6.65-6.54 (m, 1H), 6.26-6.00;5.17-5.04 (m, 1H), 4.61-3.36 (m, 4H). MS (ESI) mass calcd.C₂₃H₁₆ClF₃N₄O₂, 472.1; m/z found, 473.1 [M+H]⁺.

Example 80(±)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(1-hydroxyethyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 53(using 2-hydroxypropanehydrazide instead of acetic hydrazide in Step F.)¹H NMR (500 MHz, CDCl₃) δ 7.83-7.74 (m, 1H), 7.59-7.29 (m, 7H),6.16-5.99; 5.15-4.97 (m, 2H), 4.47-2.76 (m, 5H), 1.79-1.65 (m, 3H). MS(ESI) mass calcd. C₂₁H₁₈ClF₃N₄O₂, 450.1; m/z found, 451.2 [M+H]⁺.

Example 81(R)-(3-(tert-butyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2-chloro-3-(trifluoromethyl)phenyl)methanone

The desired product was prepared in an analogous manner to example 53(using pivalohydrazide instead of acetic hydrazide in Step F.) Theracemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 80% CO₂, 20% iPrOH)yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ 7.86-7.71 (m,1H), 7.60-7.28 (m, 7H), 6.20-6.01; 5.13-4.91 (m, 1H), 4.36-3.31 (m, 4H),1.53-1.46 (m, 9H). MS (ESI) mass calcd. C₂₃H₂₂ClF₃N₄O, 462.1; m/z found,463.1 [M+H]⁺.

Example 82(S)-(3-(tert-butyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2-chloro-3-(trifluoromethyl)phenyl)methanone

The desired product was prepared in an analogous manner to example 53(using pivalohydrazide instead of acetic hydrazide in Step F.) Theracemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 80% CO₂, 20% iPrOH)yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ 7.84-7.72 (m,1H), 7.58-7.28 (m, 7H), 6.20-6.01; 5.12-4.96 (m, 1H), 4.34-3.29 (m, 4H),1.53-1.45 (m, 9H). MS (ESI) mass calcd. C₂₃H₂₂ClF₃N₄O, 462.1; m/z found,463.1 [M+H]⁺.

Example 83(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(furan-2-yl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 53(using oxazole-2-carbohydrazide instead of acetic hydrazide in Step F.)The racemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 68% CO₂, 32% iPrOH)yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ 7.85-7.74 (m,1H), 7.65-7.30 (m, 8H), 7.21-7.13 (m, 1H), 6.65-6.52 (m, 1H), 6.23-6.04;5.19-5.05 (m, 1H), 4.61-3.34 (m, 4H). MS (ESI) mass calcd.C₂₃H₁₆ClF₃N₄O₂, 472.1; m/z found, 473.1 [M+H]⁺.

Example 84(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(furan-2-yl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 53(using oxazole-2-carbohydrazide instead of acetic hydrazide in Step F.)The racemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 68% CO₂, 32% iPrOH)yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ 7.85-7.75 (m,1H), 7.64-7.28 (m, 8H), 7.21-7.14 (m, 1H), 6.64-6.57 (m, 1H), 6.20-6.08;5.21-5.01 (m, 1H), 4.64-3.35 (m, 4H). MS (ESI) mass calcd.C₂₃H₁₆ClF₃N₄O₂, 472.1; m/z found, 473.0 [M+H]⁺.

Example 85(±)-(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

To a solution of 3-methyl-8-(pyridin-2-yl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine (200 mg, 0.766 mmol) in 5 mLof DCM was added triethylamine (0.639 mL, 4.596 mmol). The resultingreaction mixture was stirred for 5 min at room temperature and thencooled to 0° C. 2-chloro-3-(trifluoromethyl)benzoyl chloride (372 mg,1.532 mmol) was subsequently added and the reaction was stirred at 0° C.for 20 min. The reaction was quenched with water and warmed to roomtemperature then extracted three times with DCM. The combined organiclayers were dried using MgSO4 and concentrated into a residue, which waspurified via basic HPLC (Agilent prep system, Waters XBridge C18 5 um50×100 mm column, 5-95% MeCN/20 nM NH₄OH over 22 min at 80 mL/min) toprovide the racemic product (114 mg, 35.2%). ¹H NMR (500 MHz, CDCl₃) δ8.68-8.39 (m, 1H), 7.97-7.12 (m, 6H), 5.98-5.90; 5.23-5.09 (m, 1H),4.47-3.43 (m, 4H), 2.51-2.39 (m, 3H). MS (ESI) mass calcd.C₁₉H₁₅ClF₃N₅O, 421.1; m/z found, 422.0 [M+H]⁺.

Example 86(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-ethyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 53(using propionohydrazide instead of acetic hydrazide in Step F.) Theracemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 70% CO₂, 30% iPrOH)yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ 7.84-7.73 (m,1H), 7.58-7.28 (m, 7H), 6.20-6.01; 5.19-5.02 (m, 1H), 4.17-3.30 (m, 4H),2.89-2.64 (m, 2H), 1.49-1.37 (m, 3H). MS (ESI) mass calcd.C₂₁H₁₈ClF₃N₄O, 434.1; m/z found, 435.4 [M+H]⁺.

Example 87(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-ethyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 53(using propionohydrazide instead of acetic hydrazide in Step F.) Theracemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 70% CO₂, 30% iPrOH)yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ 7.87-7.71 (m,1H), 7.60-7.27 (m, 7H), 6.20-6.01; 5.19-5.01 (m, 1H), 4.16-3.28 (m, 4H),2.88-2.67 (m, 2H), 1.48-1.39 (m, 3H). MS (ESI) mass calcd.C₂₁H₁₈ClF₃N₄O, 434.1; m/z found, 435.2 [M+H]⁺.

Example 88(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-isopropyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 53(using isobutyrohydrazide instead of acetic hydrazide in Step F.) Theracemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 70% CO₂, 30% iPrOH)yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ 7.84-7.74 (m,1H), 7.58-7.28 (m, 7H), 6.19-6.01; 5.17-5.00 (m, 1H), 4.21-3.30 (m, 4H),3.08-2.92 (m, 1H), 1.52-1.44 (m, 3H), 1.44-1.37 (m, 3H). MS (ESI) masscalcd. C₂₂H₂₀ClF₃N₄O, 448.1; m/z found, 449.3 [M+H]⁺.

Example 89(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-isopropyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 53(using isobutyrohydrazide instead of acetic hydrazide in Step F.) Theracemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 70% CO₂, 30% iPrOH)yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ 7.84-7.73 (m,1H), 7.58-7.27 (m, 7H),6.19-6.01; 5.19-5.02 (m, 1H), 4.20-3.28 (m, 4H),3.09-2.92 (m, 1H), 1.51-1.44 (m, 3H), 1.43-1.37 (m, 3H). MS (ESI) masscalcd. C₂₂H₂₀ClF₃N₄O, 448.1; m/z found, 449.4 [M+H]⁺.

Example 90(±)-(2,3-dichlorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 108(using trifluoracetic anhydride instead of difluoroacetic anhydride inStep C and 2,3-dichlorobenzoyl chloride instead of2-chloro-3-(trifluoromethyl)benzoyl chloride in Step E) and was purifiedvia basic HPLC (Agilent prep system, Waters XBridge C18 5 μm 50×100 mmcolumn, 5-95% MeCN/20 nM NH₄OH over 22 min at 80 mL/min) to provide theracemic product (100 mg, 55%). ¹H NMR (500 MHz, CDCl₃) δ 7.61-7.52(m,12H), 7.52-7.17 (m, 7H), 6.34-6.11; 5.20-5.05 (m, 1H), 4.40-3.32 (m,4H). MS (ESI) mass calcd. C₁₉H₁₃Cl₂F₃N₄O, 440.1; m/z found, 441.1[M+H]⁺.

Example 91(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 85.The racemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 60% CO₂, 40% iPrOH)yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ 8.63-8.44 (m,1H), 7.97-7.13 (m, 6H), 5.99-5.91; 5.26-5.10 (m, 1H), 4.50-3.52 (m, 4H),2.51-2.43 (m, 3H). MS (ESI) mass calcd. C₁₉H₁₅ClF₃N₅O, 421.1; m/z found,421.8 [M+H]⁺.

Example 92(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 85.The racemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 60% CO₂, 40% iPrOH)yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ 8.63-8.44 (m,1H), 7.97-7.14 (m, 6H), 5.99-5.94; 5.24-5.10 (m, 1H), 4.49-3.53 (m, 4H),2.52-2.41 (m, 3H). MS (ESI) mass calcd. C₁₉H₁₅ClF₃N₅O, 421.1; m/z found,421.8 [M+H]⁺.

Example 93(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclobutyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 53(using cyclobutanecarbohydrazide instead of acetic hydrazide in Step F.)The racemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 70% CO₂, 30% iPrOH)yielding the desired product. ¹H NMR (500 MHz, CDCl₃) δ 7.83-7.74 (m,1H), 7.56-7.28 (m, 7H), 6.18-5.97; 5.13-4.98 (m, 1H), 4.08-3.27 (m, 5H),2.66-2.49 (m, 2H), 2.50-2.34 (m, 2H), 2.21-2.00 (m, 2H). MS (ESI) masscalcd. C₂₃H₂₀ClF₃N₄O, 460.1; m/z found, 461.1 [M+H]⁺.

Example 94(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclobutyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 53(using cyclobutanecarbohydrazide instead of acetic hydrazide in Step F.)The racemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 70% CO₂, 30% iPrOH)yielding the desired product. ¹H NMR (500 MHz, CDCl₃) δ 7.83-7.73 (m,1H), 7.56-7.28 (m, 7H), 6.16-5.98; 5.13-4.98 (m, 1H), 4.08-3.24 (m, 5H),2.68-2.49 (m, 2H), 2.49-2.34 (m, 2H), 2.23-2.00 (m, 2H). MS (ESI) masscalcd. C₂₃H₂₀ClF₃N₄O, 460.1; m/z found, 461.1 [M+H]⁺.

Examples 95 and 96 were prepared as described in Example 108,substituting trifluoracetic anhydride for difluoroacetic anhydride inStep C and 2-chloro-4-fluoro-3-trifluoromethyl benzoic acid for2-chloro-3-(trifluoromethyl)benzoic acid in Step E. The racemic mixturewas separated by prep HPLC (Stationary phase: CHIRALPAK AD-H 5 μm250×20mm), Mobile phase: 80% CO₂, 20% EtOH) to provide the (R) and (S)enantiomers.

Example 95(R*)-(2-chloro-4-fluoro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

¹H NMR (500 MHz, CDCl₃) δ 7.60-7.13 (m, 7H), 6.21-6.23; 6.10-6.04;5.20-5.07 (m, 1H), 4.38-4.15; 4.02-3.88; 3.78-3.38 (m, 4H). MS (ESI)mass calcd. C₂₀H₁₂ClF₇N₄O, 492.1; m/z found, 492.0.

Example 96(S*)-(2-chloro-4-fluoro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

¹H NMR (500 MHz, CDCl₃) δ 7.60-7.13 (m, 7H), 6.21-6.23; 6.10-6.04;5.20-5.07 (m, 1H), 4.38-4.15; 4.02-3.88; 3.78-3.38 (m, 4H). MS (ESI)mass calcd. C₂₀H₁₂ClF₇N₄O, 492.1; m/z found, 492.0.

Example 97(R)-(2-chloro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 108(using trifluoracetic anhydride instead of difluoroacetic anhydride inStep C) and was separated via chrial SFC (Stationary phase: CHIRALPAKAD-H 5 μm 250×20 mm), (Mobile phase: 80% CO₂, 20% iPrOH) yielding thedesired product. ¹H NMR (400 MHz, CDCl₃) δ 7.86-7.77 (m, 1H), 7.60-7.32(m, 7H), 6.26-6.08; 5.23-5.09 (m, 1H), 4.40-3.36 (m, 4H). MS (ESI) masscalcd. C₂₀H₁₃ClF₆N₄O, 474.1; m/z found, 474.7 [M+H]⁺.

Example 98(S)-(2-chloro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was separated from example 97 via chiral SFC(Stationary phase: CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 80%CO₂, 20% iPrOH) yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ7.86-7.76 (m, 1H), 7.60-7.31 (m, 7H), 6.26-6.07; 5.23-5.09 (m, 1H),4.41-3.36 (m, 4H). MS (ESI) mass calcd. C₂₀H₁₃ClF₆N₄O, 474.1; m/z found,474.8 [M+H]⁺.

Examples 99 and 100 were prepared as described in Example 108,substituting trifluoracetic anhydride for difluoroacetic anhydride inStep C and 3-chloro-2-(trifluoromethyl)isonicotinic acid for2-chloro-3-(trifluoromethyl)benzoic acid in Step E. The racemic mixturewas separated by prep HPLC (Stationary phase: CHIRALPAK AD-H 5 μm250×20mm), Mobile phase: 80% CO₂, 20% EtOH) to provide the (R) and (S)enantiomers.

Example 99(R*)-(3-chloro-2-(trifluoromethyl)pyridin-4-yl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

¹H NMR (500 MHz, CDCl₃) δ 8.78-8.59 (m, 1H), 7.61-7.20 (m, 6H),6.20-6.12; 6.04-5.92; 5.21-5.06 (m, 1H), 4.42-4.16; 4.07-3.93; 3.81-3.41(m, 4H). MS (ESI) mass calcd. C₁₉H₁₂ClF₆N₅O, 475.1; m/z found, 475.9[M+H]⁺.

Example 100(S*)-(3-chloro-2-(trifluoromethyl)pyridin-4-yl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

¹H NMR (500 MHz, CDCl₃) δ 8.78-8.59 (m, 1H), 7.61-7.20 (m, 6H),6.20-6.12; 6.04-5.92; 5.21-5.06 (m, 1H), 4.42-4.16; 4.07-3.93; 3.81-3.41(m, 4H). MS (ESI) mass calcd. C₁₉H₁₂ClF₆N₅O, 475.1; m/z found, 475.9[M+H]⁺.

Example 101(±)-(2-chloro-3-(trifluoromethyl)phenyl)(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

To a solution of8-(4-fluorophenyl)-3-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine(120 mg, 0.435 mmol) in 5 mL of DCM was added triethylamine (0.363 mL,2.610 mmol). The resulting reaction mixture was stirred for 5 min atroom temperature and then cooled to 0° C.2-chloro-3-(trifluoromethyl)benzoyl chloride (211 mg, 0.870 mmol) wassubsequently added and the reaction was stirred at 0° C. for 20 min. Thereaction was quenched with water and warmed to room temperature thenextracted three times with DCM. The combined organic layers were driedusing MgSO4 and concentrated into a residue, which was purified viabasic HPLC (Agilent prep system, Waters XBridge C18 5 um 50×100 mmcolumn, 5-95% MeCN/20 nM NH₄OH over 22 min at 80 mL/min) to provide theracemic product (124 mg, 65%). ¹H NMR (500 MHz, CDCl₃) δ 7.85-7.75 (m,1H), 7.61-7.33 (m, 4H), 7.10-6.99 (m, 2H), 6.12-5.92; 5.19-5.04 (m, 1H),4.14-3.27 (m, 4H), 2.51-2.41 (m, 3H). MS (ESI) mass calcd.C₂₀H₁₅ClF₄N₄O, 438.1; m/z found, 439.2 [M+H]⁺.

Example 102(R)-(2,3-dichlorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 108(using trifluoracetic anhydride instead of difluoroacetic anhydride inStep C and 2,3-dichlorobenzoyl chloride instead of2-chloro-3-(trifluoromethyl)benzoyl chloride in Step E) and wasseparated via chiral SFC (Stationary phase: CHIRALPAK AD-H 5 μm 250×20mm), (Mobile phase: 75% CO₂, 25% iPrOH) yielding the desired product. ¹HNMR (400 MHz, CDCl₃) δ 7.61-7.52 (m, 1H), 7.52-7.19 (m, 7H), 6.34-6.11;5.19-5.08 (m, 1H), 4.40-3.32 (m, 4H). MS (ESI) mass calcd.C₁₉H₁₃Cl₂F₃N₄O, 440.0; m/z found, 440.8 [M+H]⁺.

Example 103(S)-(2,3-dichlorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was separated from example 102 via chiral SFC(Stationary phase: CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 75%CO₂, 25% iPrOH) yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ7.61-7.53 (m, 1H), 7.53-7.19 (m, 7H), 6.33-6.12; 5.19-5.08 (m, 1H),4.40-3.31 (m, 4H). MS (ESI) mass calcd. C₁₉H₁₃Cl₂F₃N₄O, 440.0; m/zfound, 440.8 [M+H]⁺.

Example 104(R)-(2,3-dichlorophenyl)(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 101(using 2,3-dichlorobenzoyl chloride instead of2-chloro-3-(trifluoromethyl)benzoyl chloride.) The racemic product wasseparated via chiral SFC (Stationary phase: CHIRALPAK AD-H 5 μm 250×20mm), (Mobile phase: 75% CO₂, 25% iPrOH) yielding the desired product. ¹HNMR (400 MHz, CDCl₃) δ 7.60-7.51 (m, 1H), 7.47-7.15 (m, 4H), 7.10-6.98(m, 2H), 6.20-5.98; 5.20-5.02 (m, 1H), 4.14-3.23 (m, 4H), 2.53-2.40 (m,3H). MS (ESI) mass calcd. C₁₉H₁₅Cl₂FN₄O, 404.1; m/z found, 404.8 [M+H]⁻.

Example 105(S)-(2,3-dichlorophenyl)(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 101(using 2,3-dichlorobenzoyl chloride instead of2-chloro-3-(trifluoromethyl)benzoyl chloride.) The racemic product wasseparated via chiral SFC (Stationary phase: CHIRALPAK AD-H 5 μm 250×20mm), (Mobile phase: 75% CO₂, 25% iPrOH) yielding the desired product. ¹HNMR (400 MHz, CDCl₃) δ 7.60-7.50 (m, 1H), 7.47-7.16 (m, 4H), 7.10-6.98(m, 2H), 6.20-5.99; 5.18-5.03 (m, 1H), 4.16-3.21 (m, 4H), 2.53-2.44 (m,3H). MS (ESI) mass calcd. C₁₉H₁₅Cl₂FN₄O, 404.1; m/z found, 404.7 [M+H]⁻.

Example 106(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclopropyl-8-(4-fluorophenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 101(using3-cyclopropyl-8-(4-fluorophenyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazineinstead of8-(4-fluorophenyl)-3-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine.)The racemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 75% CO₂, 25% iPrOH)yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ 7.86-7.75 (m,1H), 7.59-7.27 (m, 4H), 7.11-6.98 (m, 2H), 6.13-5.92; 5.20-5.05 (m, 1H),4.25-3.27 (m, 4H), 1.79-1.65 (m, 1H), 1.29-1.17 (m, 2H), 1.16-1.04 (m,2H). MS (ESI) mass calcd. C₂₂H₁₇ClF₄N₄O, 464.1; m/z found, 464.8 [M+H]⁺.

Example 107(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclopropyl-8-(4-fluorophenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 101(using3-cyclopropyl-8-(4-fluorophenyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazineinstead of8-(4-fluorophenyl)-3-methyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine.)The racemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 75% CO₂, 25% iPrOH)yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ 7.86-7.75 (m,1H), 7.60-7.27 (m, 4H), 7.11-6.98 (m, 2H), 6.12-5.92; 5.22-5.05 (m, 1H),4.25-3.25 (m, 4H), 1.81-1.65 (m, 1H), 1.33-1.17 (m, 2H), 1.17-1.02 (m,2H). MS (ESI) mass calcd. C₂₂H₁₇ClF₄N₄O, 464.1; m/z found, 464.8 [M+H]⁺.

Example 108(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(difluoromethyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Intermediate 108A: 2-chloro-3-phenylpyrazine

Step A: 2-chloro-3-phenylpyrazine

To a solution of 2,3-dichloropyrazine (1.50 g, 10.07 mmol) andphenylboronic acid (1.23 g, 10.07 mmol) in 35 mL of DME was added Na2CO3(1.07 g, 10.07 mmol) in 15 mL of water. N2 gas was bubbled through thereaction mixture for 15 min then the flask was equipped with a condenserand purged with N2 for another 15 in before addingtetrakis(triphenylphosphine)palladium (581.75 mg, 0.503 mmol). Theresulting reaction mixture was heated to reflux (85° C.) and allowed tostir overnight. The reaction was cooled to rt and diluted with 80 mL ofwater then extracted three times with DCM. The combined organic extractswere dried with MgSO4, filtered and concentrated under reduced pressure.The resulting yellow residue was purified via silica gel chromatography(0-30% ethyl acetate/hexanes) to provide the desired product (1.39 g,72%) as a white solid. MS (ESI) mass calcd. C₁₀H₇ClN₂, 190.63; m/zfound, 191.0 [M+H]⁺.

Intermediate 108B: 2-hydrazinyl-3-phenylpyrazine

Step B: 2-hydrazinyl-3-phenylpyrazine

A neat suspension of 2-chloro-3-phenylpyrazine (1.39 g, 7.23 mmol) inhydrazine monohydrate (3.6 mL, 72.78 mmol) was placed in microwave vialand irradiates at 120° C. for 1 hour. The resulting reaction mixture wascooled down to rt and diluted with 30 mL of water and then extractedthree times with 30 mL of DCM. The combined organic extracts were driedusing MgSO4 and concentrated under reduced pressure to provide thedesired product (1.21 g, 89%). MS (ESI) mass calcd. C₁₀H₁₀N₄, 186.2; m/zfound, 187.2 [M+H]⁺.

Intermediate 108C:3-(difluoromethyl)-8-phenyl-[1,2,4]triazolo[4,3-a]pyrazine

Step C: 3-(difluoromethyl)-8-phenyl-[1,2,4]triazolo[4,3-a]pyrazine

A neat residue of 2-hydrazinyl-3-phenylpyrazine (665 mg, 3.571 mmol) wascooled to 0° C. and Difluoroacetic anhydride (4.44 mL, 35.71 mmol) wasadded drop-wise. The resulting reaction mixture was allowed to stir atroom temperature for 2 hours then concentrated into a brown residueunder reduced pressure. The brown residue was suspended in 4 mL ofpolyphosphoric acid to form a gelatinous mixture, which was heated to140° C. and stirred overnight The reaction mixture was then neutralizedto pH 7 with NaOH pellets and ice water. The resulting aqueous solutionwas extracted three times with ethyl acetate. The combined organicextracts were dried with MgSO4 and concentrated into a brown residuewhich was purified via silica gel chromatography (0-50% ethylacetate/hexanes) to provide the desired product (500 mg, 57%). ¹H NMR(500 MHz, CDCl₃) δ 8.84-8.77 (m, 2H), 8.20 (d, J=4.6 Hz, 1H), 8.12 (d,J=4.6 Hz, 1H), 7.60-7.53 (m, 3H), 7.45-7.22 (m, 1H). MS (ESI) masscalcd. C₁₂H₈F₂N₄, 246.2; m/z found, 274.1 [M+H]⁺.

Intermediate 108D:3-(difluoromethyl)-8-phenyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine

Step D:3-(difluoromethyl)-8-phenyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine

To a round-bottom flask containing a solution of3-(difluoromethyl)-8-phenyl-[1,2,4]triazolo[4,3-a]pyrazine (500 mg,2.031 mmol) in 5 mL ethanol was added 10% palladium on carbon (wetDegussa powder) (108 mg, 0.102 mmol). The resulting reaction vessel waspurged with N2 gas and fitted with a hydrogen balloon (1 atm), then thereaction mixture was stirred at rt overnight. The reaction mixture wasthen filtered through a pad of celite and concentrated under reducedpressure to provide the desired product (470 mg, 92%). MS (ESI) masscalcd. C₁₂H12F₂N₄, 250.2; m/z found, 251.1 [M+H]⁺.

Example 108(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(difluoromethyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Step E:(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(difluoromethyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

To a solution of3-(difluoromethyl)-8-phenyl-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine(150 mg, 0.600 mmol) in 5 mL of DCM was added triethylamine (0.25 mL,1.798 mmol). The resulting reaction mixture was stirred for 5 min atroom temperature and then cooled to 0° C.2-chloro-3-(trifluoromethyl)benzoyl chloride (291 mg, 1.200 mmol) wassubsequently added and the reaction was stirred at 0° C. for 20 min. Thereaction was quenched with water and warmed to room temperature thenextracted three times with DCM. The combined organic layers were driedusing MgSO4 and concentrated into a residue, which was purified viabasic HPLC (Agilent prep system, Waters XBridge C18 5 μm 50×100 mmcolumn, 5-95% MeCN/20 nM NH₄OH over 22 min at 80 mL/min) to provide theracemic product (132 mg, 48.2%). The racemic product was separated viachiral SFC (Stationary phase: CHIRALPAK AD-H 5 μm 250×20 mm), (Mobilephase: 70% CO₂, 30% iPrOH) yielding the desired product. ¹H NMR (400MHz, CDCl₃) δ 7.87-7.77 (m, 1H), 7.61-7.32 (m, 7H), 7.14-6.84 (m, 1H),6.29-6.08; 5.17-5.10 (m, 1H), 4.43-3.27 (m, 4H). MS (ESI) mass calcd.C₂₀H₁₄ClF₅N₄O, 456.1; m/z found, 456.8 [M+H]⁺.

Example 109(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(difluoromethyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was separated from example 108 via chiral SFC(Stationary phase: CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 70%CO₂, 30% iPrOH) yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ7.87-7.76 (m, 1H), 7.60-7.30 (m, 7H), 7.14-6.84 (m, 1H), 6:30-6.09;5.17-5.07 (m, 1H), 4.44-3.31 (m, 4H). MS (ESI) mass calcd.C₂₀H₁₄ClF₅N₄O, 456.1; m/z found, 456.8 [M+H]⁺.

Example 110(R)-(2,3-dichlorophenyl)(3-(difluoromethyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 108(using 2,3-dichlorobenzoyl chloride instead of2-chloro-3-(trifluoromethyl)benzoyl chloride in Step E) and wasseparated via chiral SFC (Stationary phase: CHIRALPAK AD-H 5 μm 250×20mm), (Mobile phase: 70% CO₂, 30% iPrOH) yielding the desired product. ¹HNMR (400 MHz, CDCl₃) δ 7.61-7.51 (m, 1H), 7.49-7.18 (m, 7H), 7.14-6.84(m, 1H), 6.30-6.09; 5.15-5.08 (m, 1H), 4.44-3.28 (m, 4H). MS (ESI) masscalcd. C₁₉H₁₄Cl₂F₂N₄O, 422.1; m/z found, 422.8 [M+H]⁺.

Example 111(S)-(2,3-dichlorophenyl)(3-(difluoromethyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was separated from example 110 via chiral SFC(Stationary phase: CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 70%CO₂, 30% iPrOH) yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ7.61-7.51 (m, 1H), 7.50-7.18 (m, 7H), 7.14-6.84 (m, 1H), 6:30-6.09;5.17-5.07 (m, 1H), 4.44-3.31 (m, 4H). MS (ESI) mass calcd.C₁₉H₁₄Cl₂F₂N₄O, 422.1; m/z found, 422.8 [M+H]⁺.

Example 112(R)-(2,3-dichlorophenyl)(3-methyl-8-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 85(using 2,3-dichlorobenzoyl chloride instead of2-chloro-3-(trifluoromethyl)benzoyl chloride.) The racemic product wasseparated via chiral SFC (Stationary phase: CHIRALPAK AD-H 5 μm 250×20mm), (Mobile phase: 75% CO₂, 25% iPrOH) yielding the desired product. ¹HNMR (400 MHz, CDCl₃) δ 8.62-8.43 (m, 1H), 7.96-7.09 (m, 6H), 6.10-5.94;5.20-5.07 (m, 1H), 4.45-3.57 (m, 4H), 2.52-2.39 (m, 3H). MS (ESI) masscalcd. C₁₈H₁₅Cl₂N₅O, 387.1; m/z found, 387.7 [M+H]⁺.

Example 113(S)-(2,3-dichlorophenyl)(3-methyl-8-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 85(using 2,3-dichlorobenzoyl chloride instead of2-chloro-3-(trifluoromethyl)benzoyl chloride.) The racemic product wasseparated via chiral SFC (Stationary phase: CHIRALPAK AD-H 5 μm 250×20mm), (Mobile phase: 75% CO₂, 25% iPrOH) yielding the desired product. ¹HNMR (400 MHz, CDCl₃) δ 8.61-8.42 (m, 1H), 7.94-7.08 (m, 6H), 6.11-5.90;5.22-5.07 (m, 1H), 4.46-3.57 (m, 4H), 2.54-2.41 (m, 3H). MS (ESI) masscalcd. C₁₈H₁₅Cl₂N₅O, 387.1; m/z found, 387.7 [M+H]⁺.

Example 114(R)-(2-chloro-3-(trifluoromethyl)phenyl)(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 101.The racemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 80% CO₂, 20% iPrOH)yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ 7.85-7.75 (m,1H), 7.57-7.27 (m, 4H), 7.11-6.99 (m, 2H), 6.13-5.93; 5.20-5.07 (m, 1H),4.15-3.27 (m, 4H), 2.52-2.43 (m, 3H). MS (ESI) mass calcd.C₂₀H₁₅ClF₄N₄O, 438.1; m/z found, 438.7 [M+H]⁺.

Example 115(S)-(2-chloro-3-(trifluoromethyl)phenyl)(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 101.The racemic product was separated via chiral SFC (Stationary phase:CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 80% CO₂, 20% iPrOH)yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ 7.86-7.76 (m,1H), 7.57-7.27 (m, 4H), 7.11-6.99 (m, 2H), 6.12-5.94; 5.20-5.04 (m, 1H),4.15-3.26 (m, 4H), 2.53-2.41 (m, 3H). MS (ESI) mass calcd.C₂₀H₁₅ClF₄N₄O, 438.1; m/z found, 438.7 [M+H]⁻.

Example 116(R)-(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2-methyl-3-(trifluoromethyl)phenyl)methanone

The desired product was prepared in an analogous manner to example 101(using 2-methyl-3-(trifluoromethyl)benzoyl chloride instead of82-chloro-3-(trifluoromethyl)benzoyl chloride.) The racemic product wasseparated via chiral SFC (Stationary phase: CHIRALPAK AD-H 5 μm 250×20mm), (Mobile phase: 75% CO₂, 25% iPrOH) yielding the desired product. ¹HNMR (400 MHz, CDCl₃) δ 7.76-7.66 (m, 1H), 7.47-7.27 (m, 4H), 7.11-6.96(m, 2H), 6.21-5.93; 5.21-5.12 (m, 1H), 4.13-3.28 (m, 4H), 2.53-2.18 (m,6H). MS (ESI) mass calcd. C₂₁H₁₈F₄N₄O, 418.1; m/z found, 418.8 [M+H]⁺.

Example 117(S)-(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2-methyl-3-(trifluoromethyl)phenyl)methanone

The desired product was prepared in an analogous manner to example 101(using 2-methyl-3-(trifluoromethyl)benzoyl chloride instead of82-chloro-3-(trifluoromethyl)benzoyl chloride.) The racemic product wasseparated via chiral SFC (Stationary phase: CHIRALPAK AD-H 5 μm 250×20mm), (Mobile phase: 75% CO₂, 25% iPrOH) yielding the desired product. ¹HNMR (400 MHz, CDCl₃) δ 7.77-7.65 (m, 1H), 7.47-7.27 (m, 4H), 7.13-6.98(m, 2H), 6.21-5.92; 5.20-5.14 (m, 1H), 4.15-3.29 (m, 4H), 2.55-2.16 (m,6H). MS (ESI) mass calcd. C₂₁H₁₈F₄N₄O, 418.1; m/z found, 418.8 [M+H]⁺.

Example 118(R)-(2-chloro-4-fluorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 108(using trifluoracetic anhydride instead of difluoroacetic anhydride inStep C and 2-chloro-4-fluorobenzoyl chloride instead of2-chloro-3-(trifluoromethyl)benzoyl chloride in Step E) and wasseparated via chiral SFC (Stationary phase: CHIRALPAK AD-H 5 μm 250×20mm), (Mobile phase: 70% CO₂, 30% iPrOH) yielding the desired product. ¹HNMR (400 MHz, CDCl₃) δ 7.54-7.48 (m, 1H), 7.46-7.02 (m, 7H), 6.17-6.09;5.18-5.10 (m, 1H), 4.38-3.29 (m, 4H). MS (ESI) mass calcd.C₁₉H₁₃ClF₄N₄O, 424.1; m/z found, 424.7 [M+H]⁺.

Example 119(S)-(2-chloro-4-fluorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was separated from example 118 via chiral SFC(Stationary phase: CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 70%CO₂, 30% iPrOH) yielding the desired product. ¹H NMR (500 MHz, CDCl₃) δ7.55-7.46 (m, 1H), 7.45-7.01 (m, 7H), 6.17-6.09; 5.18-5.10 (m, 1H),4.36-3.33 (m, 4H). MS (ESI) mass calcd. C₁₉H₁₃ClF₄N₄O, 424.1; m/z found,424.7 [M+H]⁺.

Example 120(R)-(2,4-dichlorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 108(using trifluoracetic anhydride instead of difluoroacetic anhydride inStep C and 2,4-dichlorobenzoyl chloride instead of2-chloro-3-(trifluoromethyl)benzoyl chloride in Step E) and wasseparated via chiral SFC (Stationary phase: CHIRALPAK AD-H 5 μm 250×20mm), (Mobile phase: 70% CO₂, 30% iPrOH) yielding the desired product. ¹HNMR (500 MHz, CDCl₃) δ 7.53-7.47 (m, 1H), 7.47-7.30 (m, 7H), 6.15-6.09;5.17-5.09 (m, 1H), 4.37-3.30 (m, 4H). MS (ESI) mass calcd.C₁₉H₁₃Cl₂F₃N₄O, 440.0; m/z found, 440.7 [M+H]⁺.

Example 121(S)-(2,4-dichlorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was separated from example 120 via chiral SFC(Stationary phase: CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 70%CO₂, 30% iPrOH) yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ7.54-7.47 (m, 1H), 7.47-7.29 (m, 7H), 6.15-6.09; 5.17-5.08 (m, 1H),4.37-3.31 (m, 4H). MS (ESI) mass calcd. C₁₉H₁₃Cl₂F₃N₄O, 440.0; m/zfound, 440.7 [M+H]⁺.

Example 122(R)-(2-methyl-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 108(using trifluoracetic anhydride instead of difluoroacetic anhydride inStep C and 2-methyl-3-(trifluoromethyl)benzoyl chloride instead of2-chloro-3-(trifluoromethyl)benzoyl chloride in Step E) and wasseparated via chiral SFC (Stationary phase: CHIRALPAK AD-H 5 μm 250×20mm), (Mobile phase: 80% CO₂, 20% iPrOH) yielding the desired product. ¹HNMR (500 MHz, CDCl₃) δ 7.77-7.68 (m, 1H), 7.60-7.27 (m, 7H), 6.31-6.06;5.25-5.15 (m, 1H), 4.43-3.40 (m, 4H), 2.51-2.18 (m, 3H). MS (ESI) masscalcd. C₂₁H₁₆F₆N₄O, 454.1; m/z found, 454.8 [M+H]⁺.

Example 123(S)-(2-methyl-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was separated from example 122 via chiral SFC(Stationary phase: CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 80%CO₂, 20% iPrOH) yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ7.78-7.67 (m, 1H), 7.60-7.28 (m, 7H), 6.33-6.06; 5.26-5.14 (m, 1H),4.43-3.37 (m, 4H), 2.51-2.16 (m, 3H). MS (ESI) mass calcd. C₂₁H₁₆F₆N₄O,454.1; m/z found, 454.8 [M+H]⁺.

Example 124(R)-(2,3-dichloro-4-fluorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 108(using trifluoracetic anhydride instead of difluoroacetic anhydride inStep C and 2,3-dichloro-4-fluorobenzoyl chloride instead of2-chloro-3-(trifluoromethyl)benzoyl chloride in Step E) and wasseparated via chiral SFC (Stationary phase: CHIRALPAK AD-H 5 μm 250×20mm), (Mobile phase: 75% CO₂, 25% iPrOH) yielding the desired product. ¹HNMR (500 MHz, CDCl₃) δ 7.51-7.47 (m, 1H), 7.43-7.13 (m, 6H), 6.33-6.06;5.17-5.09 (m, 1H), 4.37-3.34 (m, 4H). MS (ESI) mass calcd.C₁₉H₁₂Cl₂F₄N₄O, 458.0; m/z found, 458.7 [M+H]⁺.

Example 125(S)-(2,3-dichloro-4-fluorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was separated from example 124 via chiral SFC(Stationary phase: CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 75%CO₂, 25% iPrOH) yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ7.52-7.46 (m, 1H), 7.44-7.11 (m, 6H), 6.33-6.08; 5.17-5.09 (m, 1H),4.39-3.32 (m, 4H). MS (ESI) mass calcd. C₁₉H₁₂Cl₂F₄N₄O, 458.0; m/zfound, 458.7 [M+H]⁺.

Example 126(±)-(8-(1H-pyrazol-5-yl)-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2-chloro-3-(trifluoromethyl)phenyl)methanone

The desired product was prepared in an analogous manner to example 108(using 1-(2-tetrahydropyranyl)-1H-pyrazole-5-boronic acid pinacol esterinstead of phenylboronic acid in Step A and trifluoracetic anhydrideinstead of difluoroacetic anhydride in Step C) and was purified viabasic HPLC (Agilent prep system, Waters XBridge C18 5 μm 50×100 mmcolumn, 5-95% MeCN/20 nM NH₄OH over 22 min at 80 mL/min) yielding thedesired product. ¹H NMR (500 MHz, CDCl₃) δ 7.87-7.74 (m, 1H), 7.61-7.41(m, 3H), 12.01-10.82 (m, 1H), 7.41-7.37; 6.50-6.14 (m, 2H), 6.13-6.03;5.16-5.04 (m, 1H), 4.48-3.50 (m, 4H). MS (ESI) mass calcd.C₁₇H₁₁ClF₆N₆O, 464.1; m/z found, 465.1 [M+H]⁺.

Example 127(±)-(2-chloro-3-(trifluoromethyl)phenyl)(8-(pyridin-3-yl)-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 108(using 1-(2-tetrahydropyranyl)-1H-pyrazole-5-boronic acid pinacol esterinstead of phenylboronic acid in Step A and trifluoracetic anhydrideinstead of difluoroacetic anhydride in Step C) and was purified viabasic HPLC (Agilent prep system, Waters XBridge C18 5 μm 50×100 mmcolumn, 5-95% MeCN/20 nM NH₄OH over 22 min at 80 mL/min) yielding thedesired product. ¹H NMR (500 MHz, CDCl₃) δ 8.68-8.54 (m, 2H), 7.92-7.29(m, 4H), 6.20-6.11; 5.28-5.14 (m, 1H), 4.43-3.30 (m, 4H). MS (ESI) masscalcd. C₁₉H₁₂ClF₆N₅O, 475.1; m/z found, 476.1 [M+H]⁺.

Example 128(R)-(2-fluoro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was prepared in an analogous manner to example 108(using trifluoracetic anhydride instead of difluoroacetic anhydride inStep C and 2-fluoro-3-(trifluoromethyl)benzoyl chloride instead of2-chloro-3-(trifluoromethyl)benzoyl chloride in Step E) and wasseparated via chiral SFC (Stationary phase: CHIRALPAK AD-H 5 μm 250×20mm), (Mobile phase: 85% CO₂, 15% iPrOH) yielding the desired product. ¹HNMR (400 MHz, CDCl₃) δ 7.83-7.67 (m, 1H), 7.60-7.29 (m, 7H), 6.29-6.21;5.19-5.09 (m, 1H), 4.38-3.38 (m, 4H). MS (ESI) mass calcd. C₂₀H₁₃F₇N₄O,458.1; m/z found, 458.7 [M+H]⁺.

Example 129(S)-(2-fluoro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

The desired product was separated from example 128 via chiral SFC(Stationary phase: CHIRALPAK AD-H 5 μm 250×20 mm), (Mobile phase: 85%CO₂, 15% iPrOH) yielding the desired product. ¹H NMR (400 MHz, CDCl₃) δ7.82-7.67 (m, 1H), 7.62-7.28 (m, 7H), 6.30-6.21; 5.19-5.09 (m, 1H),4.39-3.35 (m, 4H). MS (ESI) mass calcd. C₂₀H₁₃F₇N₄O, 458.1; m/z found,458.7 [M+H]⁺.

Example 130(±)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Intermediate 130A:6-methyl-8-phenyl-3-(trifluoromethyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine

Step A:6-methyl-8-phenyl-3-(trifluoromethyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine

The desired product was prepared in an analogous manner to example 108(using 2,3-dichloro-5-methylpyrazine instead of 2,3-dichloropyrazine inStep A and trifluoracetic anhydride instead of difluoroacetic anhydridein Step C) yielding the desired product (502 mg, 46%). MS (ESI) masscalcd. C₁₃H₁₃F3N₄, 282.2; m/z found, 283.2 [M+H]⁺.

Example 130(±)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

Step 130B:(±)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone

In a flask purged with N2 was added6-methyl-8-phenyl-3-(trifluoromethyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine(54mg, 0.191 mmol) followed by 1 mL of THF. The resulting solution wascooled to −78° C. and n-butylLithium (2.0M in cyclohexane) (115 uL, 0.23mmol) was added. The solution was left to stir at −78° C. for 15 minutesthen a 1 mL solution of 2-chloro-3-(trifluoromethyl)benzoyl chloride (70mg, 0.287 mmol) in THF was added drop-wise. Upon complete addition, thereaction mixture was left to stir at −78° C. for 30 minutes thenquenched with addition of 3 mL of water. The resulting reaction mixturewas extracted three times with DCM and the combined organic layers weredried with MgSO4 then concentrated under reduced pressure. The resultingresidue was purified via basic HPLC (Agilent prep system, Waters XBridgeC18 5 um 50×100 mm column, 5-95% MeCN/20 nM NH₄OH over 22 min at 80mL/min) yielding the desired product. ¹H NMR (500 MHz, CDCl₃) δ7.74-7.21 (m, 8H), 5.65-5.25; (m, 1H), 4.23-3.12 (m, 3H), 1.41-1.34 (m,3H). MS (ESI) mass calcd. C₂₁H₁₅ClF₆N₄O, 488.1; m/z found, [M+H]⁺.

Example 131(±)-Benzyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2-chloro-3-(trifluoromethyl)phenyl)methanone

Intermediate 131A:3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine 7-oxide

Step A: 3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine7-oxide

To a stirring mixture of3-(trifluoromethyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine(5.00 g, 26.0 mmol) and sodium tungstate dihydrate (0.343 g, 1.04 mmol)in water (5 mL) at 0° C. was added 30% hydrogen peroxide soln (6.1 mL)dropwise over 15 min. The reaction was warmed to rt, kept at rt for 5min, then cooled again over an ice bath. After 20 min sodium bisulfate(1g) was added portionwise followed by CH₂Cl₂ (300 mL), MeOH (30 mL) andNaCl to saturate the mixture. After stirring for 16 h the solids wereallowed to settle and the liquids were decanted away. The solids werewashed with 10% MeOH/CH₂Cl₂. The organics were combined, dried withNa₂SO₄, filtered and concentrated in vacuo. The residue was purified byflash chromatography (SiO₂, 0-10% (10% 2N NH₃/MeOH)/DCM) to obtain theproduct as a yellow oil (5.36 g, 26%). ¹H NMR (500 MHz, CH₃OD) δ8.16-8.13 (m, 1H), 4.71-4.64 (m, 2H), 4.52-4.44 (m, 2H). MS (ESI) masscalcd. C₆H₅F₃N₄O, 206.04; m/z found, 206.9 [M+H]⁺.

Intermediate 131B:8-benzyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-ol

Step B:8-benzyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-ol

To a solution of3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazine 7-oxide(626 mg, 3.04 mmol) in THF (5 mL) at 0° C. was added benzylmagnesiumchloride in THF (3.8 mL, 7.6 mmol). After stirring for 30 min at 0° C.saturated ammonium chloride was added. The layers were separated and thewater layer was extracted two times more with methylene chloride. Theorganic layers were combined, dried over anhydrous Na₂SO₄, filtered andconcentrated. The residue was purified by flash chromatography (SiO₂,0-10% (10% 2N NH₃/MeOH)/DCM) to obtain the product as a yellow oil (750mg, 83%). MS (ESI) mass calcd. C₁₃H₁₃F₃N₄O, 298.10; m/z found, 299.7[M+H]⁻.

Intermediate 131C:8-benzyl-3-(trifluoromethyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine

Step C:8-benzyl-3-(trifluoromethyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine

To a solution of(8-benzyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-ol(750 mg, 2.52 mmol) in acetic acid (5 mL) and water (5 mL) was addedzinc dust (839 mg, 12.6 mmol). The reaction was stirred at 60 oC for 30min followed by the addition of more zinc (800 mg). The reaction wasallowed to stir at 40 oC for 72 h after which time it was filtered overcelite. The filtrate was evaporated in vacuo followed by the addition ofCH₂Cl₂ and aq NaHCO₃ (sat). The layers were separated and the waterlayer was extracted two times more with methylene chloride. The organiclayers were combined, dried over anhydrous Na₂SO₄, filtered andconcentrated. The residue was purified by flash chromatography (SiO₂,0-10% (10% 2N NH₃/MeOH)/DCM) to obtain the title compound (413 mg, 58%).¹H NMR (400 MHz, CD₃OD) δ 7.36-7.19 (m, 5H), 4.39 (dd, J=9.5, 3.8 Hz,1H), 4.22-4.13 (m, 1H), 4.10-4.00 (m, 1H), 3.61-3.53 (dd, J=14.0, 3.7Hz, 1H), 3.12-2.97 (m, 2H). MS (ESI) mass calcd. C₁₃H₁₃F₃N₄, 282.11; m/zfound, 283.6 [M+H]⁺.

Step D:(8-benzyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2-chloro-3-(trifluoromethyl)phenyl)methanone

To a solution of8-benzyl-3-(trifluoromethyl)-5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazine(93 mg, 0.32 mmol) in CH₂Cl₂ (1 mL) was added triethylamine (0.1 mL, 0.7mmol) and 2-chloro-3-(trifluoromethyl)benzoyl chloride. The reaction wasallowed to stir at rt for 30 min and then evaporated in vacuo. Theresidue was dissolved MeOH and purified by prep HPLC to afford the titlecompound as a white solid (95 mg, 59%). MS (ESI): mass calcd. forC₂₁H₁₅ClF₆N₄O, 488.08; m/z found, 489.1 [M+H]⁺.

Example 132(S)-(2,3-dichlorophenyl)(3-(4-hydroxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(Precursor for the Radiolabeling of(S)-(2,3-dichlorophenyl)(3-(44¹¹C]methoxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanon

Iodotrimethylsilane (71.45 μL, 0.502 mmol) was added to a solution of(S)-(2,3-dichlorophenyl)(3-(4-methoxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(70 mg, 0.167 mmol) in CH₃CN (1 mL). The mixture was stirred at 150° C.for 6 min under microwave irradation. MeOH (0.1mL) was added and thesolvents were evaporated in vacuo. The crude was purified by columnchromatography (silica, MeOH in EtOAc 0:100 to 10:90), the desiredfractions were collected and the solvent evaporated in vacuo. Theresidue was diluted into a mixture of water and CH₂Cl₂. The organiclayer was separated, dried (Na₂SO₄), filtered and the solvent wasevaporated in vacuo. Finally, the compound was triturated withdiisopropyl ether to afford(S)-(2,3-dichlorophenyl)(3-(4-hydroxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(41.4 mg, 61.2%).

Radiosynthesis, Biodistribution and Radiometabolite Analysis

HPLC analysis was performed on a LaChrom Elite HPLC system (Hitachi,Armstadt, Germany) connected to a UV spectrometer set at 220 nm. For theanalysis of radiolabeled compounds, the HPLC eluate, after passagethrough the UV detector, was led over a shielded 3-inch NaI(Tl)scintillation detector connected to a multichannel analyser (Gabi box,Raytest, Straubenhardt, Germany). The output signal was recorded andanalysed using a GINA Star data acquisition system (Raytest,Straubenhardt, Germany). Radioactivity in samples of biodistributionstudies, cell uptake experiments and radiometabolite analysis wasquantified using an automated gamma counter equipped with a 3-inchNaI(Tl) well crystal coupled to a multichannel analyser (Wallac 2480Wizard, Wallac, Turku, Finland). Results were corrected for backgroundradiation, physical decay and counter dead time.

Animals were housed in individually ventilated cages in athermoregulated (˜22° C.), humidity-controlled facility under a 12 h/12h light/dark cycle with access to food and water ad libitum. All animalexperiments were conducted according to the Belgian code of practice forthe care and use of animals, after approval from the KU LeuvenUniversity Ethics Committee for Animals.

Radiosynthesis of(S)-(2,3-dichlorophenyl)(3-(4-[¹¹C]methoxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(Example [¹¹C]55)

Carbon-11 was produced via a [¹⁴N(p,α)¹¹C] nuclear reaction. The targetgas, which was a mixture of N₂ (95%) and H₂ (5%), was irradiated using18-MeV protons at a beam current of 25 μA. The irradiation was done forabout 30 min to yield [¹¹C]methane ([¹¹C]CH₄). The [¹¹C]CH₄ was thentransferred to a home-built recirculation synthesis module and trappedon a Porapak column that was immersed in liquid nitrogen. After flushingwith helium, the condensed [¹¹C]CH₄ was converted to the gaseous phaseby bringing the Porapak loop to room temperature. This [¹¹C]CH₄ was thenreacted with vaporous I₂ at 650° C. to convert it to [¹¹C]methyl iodide([¹¹C]MeI). Subsequently, the [¹¹C]MeI was passed over a silver triflatecolumn (6 mm×50 mm) at 180° C. The resulting [¹¹C]methyl-triflate([¹¹C]MeOTf) was bubbled with a flow of helium through a solution of theprecursor(S)-(2,3-dichlorophenyl)(3-(4-hydroxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(0.2 mg) and Cs₂CO₃ (1-3 mg) in anhydrous DMF (0.2 mL). When the amountof radioactivity in the reaction vial had stabilized, the reactionmixture was left at room temperature for 3 min. The crude mixture wasdiluted with water (0.6 mL) and injected onto an HPLC system (XBridgeC₁₈, 5 μm, 4.6 mm×150 mm; Waters) eluted with a mixture of 0.05 M NaOAc(pH 5.5) and EtOH (60:40 v/v) at a flow rate of 1 mL/min. UV detectionof the HPLC eluate was performed at 254 nm. The radiolabeled product wascollected after 11 min. The collected peak corresponding to the desiredradioligand, (Example [¹¹C]55), was then diluted with saline (MiniPlasco®, Braun, Melsungen, Germany) to obtain a final EtOH concentrationof 10% and the solution was sterile filtered through 0.22 μm membranefilter (Millex®-GV, Millipore).

Chemical and radiochemical purity of Example [¹¹C]55) formulation wasanalyzed on an analytical HPLC system consisting of an XBridge C₁₈column (3.5 μm, 3.0 mm×100 mm, Waters) eluted with a mixture of 0.05 MNaOAc (pH 5.5) and CH₃CN (70:30 v/v) at a flow rate of 0.8 mL/min. UVdetection was performed at 220 nm. The crude radiolabeling mixture waspurified using semi-preparative RP-HPLC affording(S)-(2,3-dichlorophenyl)(3-(4-[11C]methoxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanonein good radiochemical yields (40-60%, relative to starting radioactivityof [¹¹C]MeOTf, non-decay corrected, n=12), with a radiochemical purityof >98% and an average specific radioactivity of 233±99 GBq/μmol at endof synthesis (EOS) (n=12). The identity of the radiotracer was confirmedby co-elution with the non-radioactive analogue after co-injection ontoan analytical HPLC system

Radiosynthesis of(S)-(2,3-dichlorophenyl)(3-(4-[¹⁸F]fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(Example [¹⁸F]68)

Fluorine-18 was produced via a [¹⁸O(p,n)¹⁸F] nuclear reaction in aCyclone 18/9 cyclotron (Ion Beam Applications, Louvain-la-Neuve,Belgium). After irradiation, [¹⁸F]F⁻ was trapped on a SepPak LightAccell plus QMA anion exchange cartridge (Waters) and eluted with akryptofix 222 14 mg/K₂CO₃ 1.2 mg dissolved in 750 μl CH₃CN/H₂O mixture(95:5 v/v) into the reaction vial. The solvent was evaporated under astream of helium at 80° C. by applying microwave heating (Resonanceinstruments 521, Skokie Ill. USA) with a power of 50 W and further driedby azeotropic distillation of traces of water using CH₃CN (1 mL in fourfractions) at the above applied microwave settings. Finally, the residuewas dried under a stream of helium at 50 W until complete dryness.

A solution of the precursor(S)-(2,3-dichlorophenyl)(3-(4-chloropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(1.5 mg), which was prepared in an analogous manner to Example 68, inDMSO (0.5 mL) was added to the dried [¹⁸F]F⁻/K₂CO₃/kryptofix residue andthe mixture was heated using microwave irradiation at 50 W and(temperature setting 170° C.) for 3 min. Next, the crude mixture wasdiluted with a mixture of EtOH/NaOAc 0.025M pH 5.5 (17/83 v/v; 0.5 mL)and injected onto the HPLC system. The HPLC system consisted of anXBridge column (C₁₈, 5 μm, 4.6 mm×150 mm; Waters) that was eluted with amixture of EtOH/NaOAc 0.025M pH 5.5 (35/65 v/v) at a flow rate of 1mL/min. UV detection of the HPLC eluate was performed at 254 nm. Theradiolabeled product(S)-(2,3-dichlorophenyl)(3-(4-[¹⁸F]fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone,(Example [¹⁸F]68), was collected after a total synthesis time of 45 minwith an average radiochemical yield of 15% and a specific activity of 22GBq/μmol.

Radiochemical purity and identity was assayed using an HPLC systemconsisting of an XBridge column (C18, 3μ, 3.0×100 mm; Waters) elutedwith NaOAc 0.05M pH 5.5/CH₃CN (70:30) at a flow rate of 0.8 ml/min. Theradioligand had a retention time of 7.7 min and had a radiochemicalpurity >98%.

Biodistribution Studies

The biodistribution studies were performed in healthy female Wistar rats(body weight, 185-220 g) at 2, 30 and 60 min after tracer injection(n=3/time point). Rats were anesthetized with isoflurane (2.5% in oxygenat a flow rate of 1 L/min) and injected with the radioligand via a tailvein. The animals were sacrificed by decapitation at the indicated timepoints. Blood and major organs were collected in tared tubes andweighed. The radioactivity in the dissected organs and blood was countedusing an automated gamma counter. For calculation of total bloodradioactivity, blood mass was assumed to be 7% of the body mass.

Biodistribution Study of [¹¹C]55

Table 2 presents the percentage injected dose (% ID) in the differentorgans and body fluids at 2, 30 and 60 min after radiotracer injection.10.0% of the injected dose was detected in the blood at 2 min afterinjection, which cleared to 5.3% at 60 min after tracer injection. Thetotal initial brain uptake of [¹¹C]55 was 0.6% at 2 min after injectionand this cleared to 0.4% at 60 min after tracer injection. At 60 minafter tracer injection, 43.8% of the injected dose was retained in theliver and the intestines. Urinary excretion of the radiotracer wasminimal, with 2.9% ID in urine and kidneys at 60 min after injection.

Table 3 shows the standardized uptake values (SUV) for different brainregions and blood. At 2 min after tracer injection, the radioactivityconcentration in the cerebellum was highest of all brain regions. Clearwash-out was observed between 2 and 30 min after tracer injection forall brain regions with relative wash-out ratios higher than 1.3 (2min-to-30 min). The radioactivity concentration at 30 and 60 min aftertracer injection was comparable for all studied brain regions, and alsofor total brain and the blood at the three studied time points.

TABLE 2 Biodistribution of [¹¹C]55 in normal rats at 2, 30 and 60minutes after tracer injection. % ID^(a) 2 min 30 min 60 min urine 0.1 ±0.1 0.9 ± 0.0 1.1 ± 0.5 kidneys 4.5 ± 0.8 1.9 ± 0.1 1.8 ± 0.2 liver 34.8± 2.1  19.4 ± 0.5  17.1 ± 0.3  spleen + pancreas 1.4 ± 0.4 0.6 ± 0.1 0.6± 0.1 lungs 2.1 ± 0.3 1.0 ± 0.1 1.1 ± 0.4 heart 1.3 ± 0.2 0.4 ± 0.0 0.4± 0.1 intestines 14.0 ± 1.8  23.8 ± 1.1  26.7 ± 9.1  stomach 1.7 ± 0.32.1 ± 1.0 5.1 ± 3.4 cerebrum 0.5 ± 0.0 0.3 ± 0.0 0.3 ± 0.1 cerebellum0.1 ± 0.0 0.1 ± 0.0 0.1 ± 0.0 blood 10.0 ± 2.4  5.2 ± 0.6 5.3 ± 0.6carcass 35.1 ± 4.1  46.9 ± 0.5  43.2 ± 5.3  ^(a)Percentage of injecteddose calculated as counts per minute (cpm) in organ/total cpm recovered.Data are expressed as mean ± SD; n = 3 per time point.

TABLE 3 [¹¹C]55 concentration in the different rat brain regions andblood at 2, 30 and 60 minutes after tracer injection. SUV^(a) 2 min 30min 60 min striatum 0.78 ± 0.0 0.45 ± 0.0 0.50 ± 0.1 hippocampus 0.74 ±0.0 0.43 ± 0.0 0.52 ± 0.1 cortex 0.80 ± 0.2 0.58 ± 0.1 0.65 ± 0.1 restof cerebrum 0.86 ± 0.0 0.46 ± 0.0 0.53 ± 0.1 whole cerebrum 0.83 ± 0.00.46 ± 0.0 0.54 ± 0.1 cerebellum 1.02 ± 0.1 0.53 ± 0.0 0.59 ± 0.1 blood1.42 ± 0.3 0.74 ± 0.1 0.75 ± 0.1 ^(a)Calculated as (radioactivity in cpmin organ/weight of organ in grams)/(total cpm recovered/body weight ratin grams). Data are expressed as mean ± SD; n = 3 per time point.

Rat Plasma Radiometabolite Analysis of [¹¹C]55

Radiometabolites of [¹¹C]55 in plasma of normal female Wistar rats (n=2)were quantified at 30 min after tracer injection. The Chromolith C₁₈column was eluted with gradient mixtures of 0.05 M NaOAc (pH 5.5) (A)and CH₃CN (B) (0-4 min: isocratic 0% B and flow rate of 0.5 mL/min; 4-14min: linear gradient 0% B to 90% B and flow rate of 1 mL/min; and 14-17min: isocratic 90% B and flow rate of 1mL/min). UV detection was done at220 nm. The reconstructed radiochromatogram demonstrated two peaks,corresponding to intact [¹¹C]55 eluting at 10 min and a polarradiometabolite eluting at 2 min (chromatograms not shown). 30 min afterradiotracer injection, 70±6% of the recovered radioactivity in theplasma was in the form of intact tracer and 30±6% was in the form ofpolar radiometabolite(s). The fraction of more lipophilicradiometabolites eluting after the intact tracer was negligible (<1.5%).

Perfused Rat Brain Radiometabolite Analysis of [¹¹C]55

Radiometabolites of [¹¹C]55 in perfused cerebrum and cerebellum ofnormal female Wistar rats (n=2) were quantified at 30 min after tracerinjection. Homogenates were analysed using an analytical XBridge column(C₁₈, 5 μm, 3×100 mm; Waters) eluted with a mixture of 0.05 M sodiumacetate (pH 5.5) and CH₃CN (65:35 v/v) at a flow rate of 0.8 mL/min. UVdetection was performed at 220 nm. The reconstructed radiochromatogramsfrom perfused rat cerebellum and cerebrum HPLC analysis at 30 min posttracer injection showed only one radioactive peak corresponding tointact [¹¹C]55 eluting at 9 min (chromatograms not shown). Both thefraction of more polar and more lipophilic radiometabolites werenegligible (<2%).

The studies using [¹⁸F]68, were performed in a manner analogus manner tothose performed with[¹¹C]55 and the results of those experiments areshown in Tables 4 and 5.

Biodistribution Study of [¹⁸F]68

TABLE 4 Biodistribution of [¹⁸F]68 in normal rats at 2, 30 and 60minutes after tracer injection. % ID^(a) 2 min 30 min 60 min urine 0.1 ±0.0 8.4 ± 1.8 8.4 ± 1.8 kidneys 3.3 ± 0.5 1.1 ± 0.2 0.9 ± 0.1 liver 34.6± 2.4  7.5 ± 0.6 3.61 ± 0.3  spleen + pancreas 1.3 ± 0.2 0.3 ± 0.1 0.2 ±0.0 lungs 1.6 ± 0.1 0.7 ± 0.1 0.6 ± 0.2 heart 0.9 ± 0.1 0.2 ± 0.0 0.1 ±0.0 intestines 10.6 ± 2.1  20.9 ± 6.0  11.2 ± 0.6  stomach 1.5 ± 0.5 1.6± 0.9 10.7 ± 3.3  cerebrum 0.6 ± 0.0 0.1 ± 0.0 0.1 ± 0.0 cerebellum 0.1± 0.0 0.0 ± 0.0 0.0 ± 0.0 blood 6.8 ± 0.6 4.3 ± 0.3 2.0 ± 0.5 carcass40.8 ± 0.8  56.6 ± 2.8  60.4 ± 2.3  bone^(b) 8.8 ± 0.8 44.5 ± 3.8  64.5± 5.9  ^(a)Percentage of injected dose calculated as counts per minute(cpm) in organ/total cpm recovered. Data are expressed as mean ± SD; n =3 per time point. ^(b)calculated to estimated total bone tissue (% ID/gbone * body mass * 0.12)

TABLE 5 [¹⁸F]68 concentration in the different rat brain regions andblood at 2, 30 and 60 minutes after tracer injection. SUV^(a) 2 min 30min 60 min striatum 1.19 ± 0.13 0.24 ± 0.05 0.19 ± 0.03 hippocampus 1.11± 0.10 0.23 ± 0.04 0.19 ± 0.03 cortex 1.27 ± 0.13 0.94 ± 0.29 0.69 ±0.17 rest of cerebrum 1.20 ± 0.11 0.31 ± 0.06 0.25 ± 0.04 whole cerebrum1.20 ± 0.11 0.31 ± 0.06 0.25 ± 0.04 cerebellum 1.21 ± 0.22 0.33 ± 0.070.38 ± 0.08 blood 0.97 ± 0.08 0.61 ± 0.04 0.29 ± 0.07 ^(a)Calculated as(radioactivity in cpm in organ/weight of organ in grams)/(total cpmrecovered/body weight rat in grams). Data are expressed as mean ± SD; n= 3 per time point.

Pharmacological Examples

The in vitro affinity of the compounds of the invention for the rat andhuman P2X7 receptor was determined using a human peripheral bloodmononuclear cells (PBMCs), a human whole blood assay, a Ca²⁺ flux andradioligand binding assay in recombinant human P2X7 cells andrecombinant rat P2X7 cells. In Table 6, when the data cell has been leftblank, it is intended to mean that the compound was not tested in thatassay. The data represented in Tables 2 may represent a value from asingle determination or when the experiment was run more than once, thedata represent averages from between 2-12 runs.

P2X7 Antagonism in Human Peripheral Blood Mononuclear Cells (PBMCs) andHuman Whole Blood.

Human blood was collected using a blood donor program. PBMCs wereisolated from blood using a Ficoll density gradient technique. Briefly,blood was laid on Ficoll solution and centrifuged at RT for 20 minutesat 2000 rpm. The buffy layer (between red blood cells and plasma) wascarefully collected by aspiration, washed with PBS and centrifuged againat 1500 rpm for 15 minutes. The resulting cell pellet was washed andplated on 96 well-plates for experiments. For the Human Whole Bloodexperiments, 150 μl of human blood was platted on 96 well-plates.Lipopolysaccharide (LPS) (30 ng/ml) was added to each well and incubatedfor 1 hour. Test compounds were then added and incubated for 30 minutes.The P2X7 agonist, 2′(3′)-O-(4-benzoylbenzoyl) adenosine 5′ -triphosphate(Bz-ATP) was then added at a final concentration of 0.5 mM (PBMC) or 1mM (blood). Cells were incubated for an additional 1.5 hours. At thatpoint, supernatant was collected and stored for IL-1β assay usingmanufacturer's protocol for enzyme-linked immunosorbent assay (ELISA).Data was expressed as percent control, where control is defined as thedifference in IL-1β release in LPS+Bz-ATP samples and LPS only samples.Data was plotted as response (% control) versus concentration togenerate IC₅₀ values. In Tables 2, this data is represented by PBMC 1 μM(% control) and PBMC 10 μM (% control) and human whole blood IC₅₀ (μM).Data are analyzed and graphed on Graphpad Prism 5. For analysis, eachconcentration point is averaged from triplicate values and the averagedvalues are plotted on Graphpad Prism. The IC₅₀ for each compound is thenuploaded into 3DX.

P2X7 Antagonism in Recombinant Human P2X7 Cells or Recombinant Rat P2X7Cells: (a) Ca²⁺ Flux and (b) Radioligand Binding

(a) Ca²⁺ flux: 1321N1 cells expressing the recombinant human or rat P2X7channel was cultured in HyQ DME/(HyClone/Dulbecco's Modified EagleMedium) high glucose supplemented with 10% Fetal Bovine Serum (FBS) andappropriate selection marker. Cells were seeded at a density of 25000cells/well (96-well clear bottom black walled plates) in 100 μlvolume/well. On the day of the experiment, cell plates were washed withassay buffer, containing (in mM): 130 NaCl, 2 KCl, 1 CaCl₂, 1 MgCl₂, 10HEPES, 5 glucose; pH 7.40 and 300 mOs. After the wash, cells were loadedwith the Calcium-4 dye (Molecular Device) and incubated in the dark for60 minutes. Test compounds were prepared at 250× the test concentrationin neat DMSO. Intermediate 96-well compound plates were prepared bytransferring 1.2 μL of the compound into 300 μL of assay buffer. Afurther 3× dilution occurred when transferring 50 μL/well of thecompound plate to 100 μL/well in the cell plate. Cells were incubatedwith test compounds and dye for 30 minutes. Calcium dye fluorescence wasmonitored in FLIPR as the cells were challenged by adding 50 μL/well ofBzATP (final concentration is 250 μM BzATP (human and rat)). Thefluorescence change was measured 180 seconds after adding the agonist.Peak fluorescence was plotted as a function of BzATP concentration usingOrigin 7 software and the resultant IC₅₀ is shown in Tables 2 under thecolumn headings FLIPR (human) IC₅₀ (μM) and FLIPR (rat) IC₅₀ (μM).

(b) Radioligand binding: human or rat P2X7-1321N1 cells were collectedand frozen @−80° C. On the day of the experiment, cell membranepreparations were made according to standard published methods. Thetotal assay volume was 100 μl:10 μl compound (10×)+(b) 40 μl tracer(2.5×)+50 μl membrane (2×). The tracer used for the assay was tritiatedA-804598. The compound can be prepared as described in the literature.(Donnelly-Roberts, D. Neuropharmacology 2008, 56 (1), 223-229.)Compounds, tracer and membranes were incubated for 1 hour @4° C. Theassay was terminated by filtration (GF/B filters pre-soaked with 0.3%PEI) and washed with washing buffer (Tris-HCl 50 mM). The IC₅₀ generatedin the binding assay was corrected for tracer concentration and affinityof the tracer to derive at the affinity (K_(i)) of the test compounds.The data are presented in Table 6 under the headings: P2X7 human K_(i)(μM) and P2X7 rat K_(i) (μM). Data are analyzed and graphed on GraphpadPrism 5. For analysis, each concentration point is averaged fromtriplicate values and the averaged values are plotted on Graphpad Prism.

TABLE 6* P2X7 activity of the compounds of Formula (I) in a panel ofin-vitro assays FLIPR FLIPR Human PBMC PBMC P2X7 P2X7 (human) (rat)whole blood 1 μM 10 μM human rat IC₅₀ IC₅₀ IC₅₀ Ex # (% control) (%control) K_(i) (μM) K_(i) (μM) (μM) (μM) (μM) 1 −11.8 nt 0.0550 nt0.0065 1.2070 nt 2 15.0 7.1 0.0214 0.0093 0.0013 0.8153 0.009 3 100.4 ntnt 1.7783 >10 >10 nt 4 98.2 nt nt nt nt nt nt 5 88.7 nt nt nt nt nt nt 6100.4 nt nt 0.5012 1.2589 15.8489 nt 7 99.9 nt nt 0.3162 1.9953 10.0000nt 8 13.9 nt 0.0427 nt 0.0286 0.1600 nt 9 16.1 nt 0.0437 nt 0.01791.0233 nt 10 6.5 nt 0.0955 nt 0.0152 0.0198 nt 11 1.4 nt 0.0468 nt0.0070 1.3772 nt 12 nt 15.0 0.0158 0.0045 0.0035 0.1023 nt 13 nt 14.91.5849 0.3162 0.2972 >10 nt 14 nt 8.9 0.0316 0.0050 0.0109 0.0240 nt 15nt 49.4 3.1623 0.5012 8.5114 >10 nt 16 nt 14.4 0.1000 nt 0.0195 0.0177nt 17 nt 3.0 0.0794 nt 0.0060 0.0650 nt 18 nt 102.4 nt nt 1.4656 2.2387nt 19 nt 7.1 0.0251 0.0079 0.0064 0.0062 0.182 20 nt 10.6 0.0398 nt0.0105 0.0512 nt 21 nt 7.0 0.0282 nt 0.0102 0.0091 0.035 22 nt 2.90.0200 nt 0.0100 0.0050 0.016 23 nt 6.2 0.0631 nt 0.0146 0.0092 0.006 24nt 8.9 0.0219 nt 0.0068 0.0047 0.025 25 nt 4.7 0.0372 nt 0.0100 7.8886nt 26 nt 28.0 nt nt 4.1305 3.9537 nt 27 nt 20.4 nt nt 1.6634 2.9648 nt28 nt 19.8 nt nt 7.4817 3.7757 nt 29 nt −0.5 nt nt 3.5481 2.9717 nt 30nt −9.6 0.0501 nt 0.0838 0.9268 1.585 31 nt −11.8 0.0079 nt 0.00670.0753 0.016 33 nt 5.9 0.3162 nt 0.3681 2.3496 nt 34 nt 18.1 nt nt12.8529 >10 nt 35 nt 19.9 nt nt >10 >10 nt 36 nt 8.1 0.1259 nt 0.05530.0111 nt 37 nt 4.8 0.2512 nt 0.1718 4.5920 nt 38 nt 25.6 nt 0.05629.9312 7.6736 nt 39 nt 22.0 nt nt 2.4322 9.4406 nt 40 nt 39.8 nt nt9.0365 14.7571 nt 41 nt 33.5 nt nt >10 10.6905 nt 42 nt 28.3 nt 0.01862.1257 9.2257 nt 43 nt 31.7 nt 0.1334 9.7051 >10 nt 44 nt 8.4 nt nt3.9174 1.4588 nt 45 nt 11.7 nt nt 1.8155 0.4083 nt 46 nt 4.4 nt nt2.5410 2.4210 nt 47 nt 36.0 nt nt 10.3753 1.6069 nt 48 nt 31.2 nt nt1.6634 0.6368 nt 49 nt 20.4 nt nt 4.1115 2.7290 nt 50 nt 41.0 nt nt10.0000 1.6827 nt 51 nt 17.5 nt nt 1.9320 0.5781 nt 52 nt 40.5 nt nt7.0469 2.0893 nt 53 nt 6.8 0.0158 0.0398 0.0020 0.0628 0.079 54 nt 0.80.0141 0.0100 0.0197 1.8239 nt 55 nt −1.3 0.0063 0.0010 0.0126 0.0200 nt56 nt 102.0 nt nt nt nt nt 57 nt 83.5 nt nt nt nt nt 58 nt 93.9 nt nt ntnt nt 59 nt 69.8 nt nt nt nt nt 60 nt 54.0 nt nt nt nt nt 61 nt 29.3 ntnt 0.3396 >10 nt 62 nt 83.0 nt nt nt nt nt 63 nt 81.5 nt nt nt nt nt 64nt 81.2 nt nt nt nt nt 65 nt 23.9 nt nt >10 >10 nt 66 nt −0.5 0.00790.0020 0.0027 0.0269 nt 67 nt −3.7 0.3162 nt 0.4831 2.0464 nt 68 nt 7.30.0063 0.0016 0.0052 0.0066 nt 69 nt 5.6 0.0032 0.0025 0.0031 0.3350 nt70 nt 10.8 0.0126 0.0040 0.0069 0.0077 nt 71 nt 16.1 nt nt 1.2218 >10 nt72 nt 25.9 nt 0.1778 8.5901 >10 nt 73 nt 52.6 nt nt 0.0068 0.1072 nt 74nt 39.9 nt nt 0.0049 0.0101 nt 75 nt 23.8 0.0288 0.0251 0.0529 0.5416 nt76 nt 22.6 0.0100 0.0050 0.0067 0.0168 nt 77 nt 14.8 nt nt 0.5888 1.1092nt 78 nt 32.3 nt nt 0.0143 6.6069 nt 79 nt −0.9 0.1000 nt 0.0151 0.0071nt 80 nt 10.7 0.0200 nt 0.0563 0.3954 nt 81 nt 10.1 0.0501 0.0089 0.01130.0270 nt 82 nt 1.6 nt nt 0.9594 1.8493 nt 83 nt 17.6 nt nt 1.79060.9977 nt 84 nt 32.6 0.0200 nt 0.0025 0.0031 nt 85 nt 11.0 0.0398 nt0.0301 1.0186 nt 86 nt 12.3 0.0126 0.0100 0.0023 0.0585 nt 87 nt 12.3 ntnt 3.8107 9.9312 nt 88 7.4 0.0200 0.0251 0.0102 0.1662 89 nt 10.3 nt nt0.9795 >10 nt 90 nt 2.3 0.0200 nt 0.0119 0.9638 nt 91 nt 1.9 0.0316 nt0.0075 2.1316 nt 92 nt 37.1 nt nt 0.7551 17.6604 nt 93 nt 7.9 0.01580.0063 0.0081 0.0178 nt 94 nt −3.8 nt nt 0.4335 2.1577 nt 95 nt 8.90.0316 nt 0.0097 0.2113 nt 96 nt 43.6 nt nt 4.8865 >10 nt 97 nt −1.70.0126 0.0047 0.0078 0.0428 nt 98 nt 44.1 nt nt 5.5081 >10 nt 99 nt 4.90.0174 0.0063 0.0091 0.0348 nt 100 nt 102.0 nt nt nt nt nt 101 nt 12.30.0316 nt 0.0278 5.0583 nt 102 nt −20.1 0.0100 0.0295 0.0105 0.4883 nt103 nt 15.0 nt nt 1.3964 >10 nt 104 nt 59.1 nt nt 4.4771 >10 nt 105 nt−16.6 0.0219 nt 0.0986 9.9541 nt 106 nt 26.7 nt nt >10 >10 nt 107 nt−25.8 0.0100 nt 0.0128 0.1782 nt 108 nt −4.2 0.0058 0.0100 0.0086 0.0816nt 109 nt 42.7 nt nt >10 >10 nt 110 nt −2.2 0.0079 0.0166 0.0034 0.4406nt 111 nt 67.2 nt nt >10 >10 nt 112 nt 6.8 0.0447 nt 0.1340 2.8249 nt113 nt 54.0 nt nt 3.8107 >10 nt 114 nt 15.6 nt nt 4.0832 >10 nt 115 nt−9.9 0.0100 nt 0.0080 0.6227 nt 116 nt 59.5 nt nt nt nt nt 117 nt 2.50.0200 nt 0.0640 7.0307 nt 118 nt −22.9 nt nt 0.9205 19.6336 nt 119 nt87.3 nt nt nt nt nt 120 nt −16.0 0.0501 nt 0.4764 >10 nt 121 nt 79.6 ntnt nt nt nt 122 nt −5.4 0.0100 nt 0.0098 0.2618 nt 123 nt 88.6 nt nt ntnt nt 124 nt −28.8 0.0079 nt 0.0106 0.2884 nt 125 nt −14.1 nt nt11.7219 >10 nt 126 nt 2.1 nt nt 1.5488 >10 nt 127 nt 10.4 0.1259 nt0.2553 28.2488 nt 128 nt 2.0 0.0501 nt 0.0685 0.2911 nt 129 nt 114.8 ntnt nt nt nt 130 nt 12.4 nt nt >10 >10 nt 131 nt nt nt nt nt nt nt *meansnot tested

What is claimed:
 1. A compound of Formula (I):

and enantiomers or diastereomers thereof; and pharmaceuticallyacceptable salts thereof; wherein: R^(a) is

R¹ is halo or C₁-C₃alkyl; R² is independently selected from the groupconsisting of: H, halo, and C₁-C₃perhaloalkyl; R³ is H or halo; R⁴ ishalo, R⁵ is halo or C₁-C₃perhaloalkyl; R^(b) is independently selectedfrom the group consisting of:

Wherein: R⁶, R⁹, R¹⁰, and R¹²are independently H or halo; R⁷ and R¹³ areindependently selected from the group consisting of: H, halo andOC₁-C₃alkyl; R⁸ is independently selected from the group consisting of:H, halo, OH and OC₁-C₃alkyl; R¹¹ is independently selected from thegroup consisting of: H, halo and C₁-C₃perhaloalkyl; R^(c) is selectedfrom the group consisting of:

R^(d) and R^(e) are independently H or C₁-C₃alkyl; and provided that atleast one of R^(c), R^(d) and R^(e) are not H.
 2. A compound as claimedin claim 1 wherein, R^(a) is


3. A compound as claimed in claim 1 wherein, R^(a) is


4. A compound as claimed in claim 1 wherein, R^(a) is

and R¹ is halo.
 5. A compound as claimed in claim 1 wherein R^(a) is

and R¹ is C₁-C₃alkyl.
 6. A compound as claimed in claim 1 wherein R^(a)is

and R² is C₁-C₃perhaloalkyl.
 7. A compound as claimed in claim 1 whereinR^(a) is

and R² is halo.
 8. A compound as claimed in claim 1 wherein R^(a) is

and R³ is H.
 9. A compound as claimed in claim 1 wherein R^(a) is

R¹ is halo, R² is C₁-C₃perhaloalkyl, and R³ is H.
 10. A compound asclaimed in claim 1 wherein R^(a) is

and R¹, R², and R³ are halo.
 11. A compound as claimed in claim 1wherein R^(a) is

R¹ and R³ are halo and R² is H.
 12. A compound as claimed in claim 1wherein R^(a) is

R¹ and R² are halo and R³ is H.
 13. A compound as claimed in claim 1wherein R^(a) is

R⁴ is halo and R⁵ is C₁-C₃perhaloalkyl.
 14. A compound as claimed inclaim 1 wherein R^(b) is independently selected from the groupconsisting of:


15. A compound as claimed in claim 1 wherein R^(b) is independentlyselected from the group consisting of:


16. A compound as claimed in claim 1 wherein R^(b) is independentlyselected from the group consisting of: C₃-C₆ cycloalkyl and C₁-C₄ alkyl.17. A compound as claimed in claim 1 wherein R^(b) is


18. A compound as claimed in claim 1 wherein R^(b) is


19. A compound as claimed in claim 1 wherein R^(b) is


20. A compound as claimed in claim 1 wherein R^(b) is

R⁶ and R⁷ are H and R⁸ is OCH₃.
 21. A compound as claimed in claim 1wherein R^(b) is

and R⁶, R⁷ and R⁸ are H.
 22. A compound as claimed in claim 1 whereinR^(b) is

and R⁸ is OH, and R⁶ and R⁷ are H.
 23. A compound as claimed in claim 1wherein R^(b) is


24. A compound as claimed in claim 1 wherein R^(b) is


25. A compound as claimed in claim 1 wherein R^(b) is

R⁹, R¹⁰ and R¹² are H and R¹¹ is F.
 26. A compound as claimed in claim 1wherein R^(b) is


27. A compound as claimed in claim 1 wherein R^(b) is


28. A compound as claimed in claim 1 wherein R^(c) is H or CH₃.
 29. Acompound as claimed in claim 1 wherein R^(c) is selected from the groupconsisting of:


30. A compound as claimed in claim 1 wherein R^(c) is


31. A compound as claimed in claim 1 wherein R^(c) is:


32. A compound as claimed in claim 1 wherein R^(d) is CH₃.
 33. Acompound as claimed in claim 1 wherein R^(e) is CH₃.
 34. A compound asclaimed in claim 1 wherein R^(c) is CH₃ and R^(d) and R^(e) are H.
 35. Acompound as claimed in claim 1 wherein R^(d) is CH₃ and R^(c) and R^(e)are H.
 36. A compound as claimed in claim 1 wherein R^(e) is CH₃ andR^(c) and R^(d) are H.
 37. A compound as claimed in claim 1 whereinR^(a) is

R¹ and R² are Cl, R^(c) is CH₃, R^(b) is

and R^(d), R^(e), R³, R⁶, R⁷ and R⁸ are H.
 38. A compound as claimed inclaim 1 wherein R^(a) is

R¹ and R² are Cl, R^(d) is CH₃, R^(b)

is R^(c), R^(e), R³, R⁹, R¹⁹ and R¹² are H and R¹¹ is F.
 39. A compoundas claimed in claim 1 wherein R^(a) is

R¹ is Cl, and R² is CF₃, R^(d) is CH₃, R^(b) is

R^(c), R^(e), R³, R⁹, R¹⁹ and R¹² are H and R¹¹ is F.
 40. A compound asclaimed in claim 1 wherein R^(a) is

R¹ and R² are Cl, R^(d) is CH₃, R^(b) is

R⁸ is OCH₃, and R^(c), R^(e), R³, R⁶, and R⁷ are H.
 41. A compound asclaimed in claim 1 wherein R^(a) is

R¹ is Cl, and R² is CF₃, R^(d) is CH₃, R^(c) is

R^(b) is

and R^(d), R^(e), and R³ are H.
 42. A compound as claimed in claim 1wherein R^(a) is

R¹ is Cl, and R² is CF₃, R^(d) is CH₃, R^(c) is

R^(b) is

and R^(d), R^(e), and R³ are H.
 43. A compound as claimed in claim 1wherein R^(a) is

R¹ is Cl, and R² is CF₃, R^(d) is CH₃, R^(c) is

R^(b) is

and R^(d), R^(e), and R³ are H.
 44. A compound selected from the groupconsisting of:(2,3-dichlorophenyl)(8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2,3-dichlorophenyl)(8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;2-chloro-3-(trifluoromethyl)phenyl)(5-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(2,3-dichlorophenyl)(5-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(2-chloro-3-(trifluoromethyl)phenyl)(3-(4-fluorophenyl)-5-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(2,3-dichlorophenyl)(3-(4-fluorophenyl)-5-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(2-chloro-3-(trifluoromethyl)phenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(2,3-dichlorophenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(2,3-dichlorophenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2,3-dichlorophenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(3-chloro-2-(trifluoromethyl)pyridin-4-yl)(8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(2-chloro-3-(trifluoromethyl)phenyl)(8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2,3-dichlorophenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(2-fluoro-3-(trifluoromethyl)phenyl)(8-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(6-methyl-3-(pyrazin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-(pyrazin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(furan-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(2-chloro-3-(trifluoromethyl)phenyl)(3-(4-fluorophenyl)-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(3-(3-fluoro-4-(trifluoromethyl)phenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(3-fluoro-4-(trifluoromethyl)phenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-3-(3,4,5-trifluorophenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(6-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(3-(4-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone(2,3-dichlorophenyl)(5-methyl-3-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(2-chloro-3-(trifluoromethyl)phenyl)(8-methyl-3-(4-(trifluoromethyl)phenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(2-chloro-3-(trifluoromethyl)phenyl)(8-methyl-3-(pyrazin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(2-chloro-3-(trifluoromethyl)phenyl)(3-(4-chlorophenyl)-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(3-(2-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(2-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichloro-4-fluorophenyl)(3-(2-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(3-(3-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(3-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichloro-4-fluorophenyl)(3-(3-fluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(3-(2,3-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(2,3-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichloro-4-fluorophenyl)(3-(2,3-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(3-(3,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(3,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichloro-4-fluorophenyl)(3-(3,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(3-(2,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(2,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichloro-4-fluorophenyl)(3-(2,4-difluorophenyl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(3-(6-fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(3-(4-methoxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(2-chlorophenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(3,4-difluoro-2-methylphenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(2-chloro-4-fluorophenyl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(2,3-dichloropyridin-4-yl)(6-methyl-3-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(3-cyclohexyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2,3-dichlorophenyl)methanone;(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclohexyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(3-cyclohexyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2,3-dichloro-4-fluorophenyl)methanone;(3-cyclopropyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2,3-dichlorophenyl)methanone;(3-cyclopropyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2,3-dichloro-4-fluorophenyl)methanone;(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclopropyl-8-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(3-(4-fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(3-(5-fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(5-fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;((S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(5-methoxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(3-(5-methoxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(3-(5-fluoropyrimidin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(3-(5-fluoropyrimidin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(±)-(2-chloro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclopropyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclopropyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(5-methoxypyrimidin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(±)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(furan-2-yl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(±)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(1-hydroxyethyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(3-(tert-butyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2-chloro-3-(trifluoromethyl)phenyl)methanone;(S)-(3-(tert-butyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2-chloro-3-(trifluoromethyl)phenyl)methanone;(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(furan-2-yl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(furan-2-yl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(±)-(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-ethyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-ethyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-isopropyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-isopropyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(±)-(2,3-dichlorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-(pyridin-2-yl)-5,6-dihydro-[[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-methyl-8-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclobutyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclobutyl-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R*)-(2-chloro-4-fluoro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S*)-(2-chloro-4-fluoro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2-chloro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R*)-(3-chloro-2-(trifluoromethyl)pyridin-4-yl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S*)-(3-chloro-2-(trifluoromethyl)pyridin-4-yl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(±)-(2-chloro-3-(trifluoromethyl)phenyl)(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2,3-dichlorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2,3-dichlorophenyl)(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclopropyl-8-(4-fluorophenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-cyclopropyl-8-(4-fluorophenyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(difluoromethyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(3-(difluoromethyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2,3-dichlorophenyl)(3-(difluoromethyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(3-(difluoromethyl)-8-phenyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2,3-dichlorophenyl)(3-methyl-8-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(3-methyl-8-(pyridin-2-yl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2-chloro-3-(trifluoromethyl)phenyl)(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-3-(trifluoromethyl)phenyl)(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2-methyl-3-(trifluoromethyl)phenyl)methanone;(S)-(8-(4-fluorophenyl)-3-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2-methyl-3-(trifluoromethyl)phenyl)methanone;(R)-(2-chloro-4-fluorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-chloro-4-fluorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2,4-dichlorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,4-dichlorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2-methyl-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-methyl-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2,3-dichloro-4-fluorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichloro-4-fluorophenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(±)-(8-(1H-pyrazol-5-yl)-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2-chloro-3-(trifluoromethyl)phenyl)methanone;(±)-(2-chloro-3-(trifluoromethyl)phenyl)(8-(pyridin-3-yl)-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(R)-(2-fluoro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2-fluoro-3-(trifluoromethyl)phenyl)(8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(±)-(2-chloro-3-(trifluoromethyl)phenyl)(6-methyl-8-phenyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(±)-benzyl-3-(trifluoromethyl)-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)(2-chloro-3-(trifluoromethyl)phenyl)methanone;(S)-(2,3-dichlorophenyl)(3-(4-hydroxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone;(S)-(2,3-dichlorophenyl)(3-(4-[¹¹C]methoxypyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanoneand(S)-(2,3-dichlorophenyl)(3-(4-[¹⁸F]fluoropyridin-2-yl)-6-methyl-5,6-dihydro-[1,2,4]triazolo[4,3-a]pyrazin-7(8H)-yl)methanone.45. A pharmaceutical composition, comprising: (a) a therapeuticallyeffective amount of at least one compound independently selected fromcompounds of Formula (I):

and enantiomers or diastereomers thereof; and pharmaceuticallyacceptable salts thereof; wherein: R^(a) is

R¹ is halo or C₁-C₃alkyl; R² is independently selected from the groupconsisting of: H, halo, and C₁-C₃perhaloalkyl; R³ is H or halo; R⁴ ishalo, R⁵ is halo or C₁-C₃perhaloalkyl; R^(b) is independently selectedfrom the group consisting of:

Wherein: R⁶, R⁹, R¹⁰, R¹², R¹⁴ are independently H or halo; R⁷ and R¹³are independently selected from the group consisting of: H, halo andOC₁-C₃alkyl; R⁸ is independently selected from the group consisting of:H, halo, OH and OC₁-C₃alkyl; R¹¹ is independently selected from thegroup consisting of: H, halo and C₁-C₃perhaloalkyl; R^(c) is selectedfrom the group consisting of:

R^(d) and R^(e) are independently H or C₁-C₃alkyl; and provided that atleast one of R^(c), R^(d) and R^(e) are not H; and (b) at least onepharmaceutically acceptable excipient.
 46. A pharmaceutical compositioncomprising a therapeutically effective amount of at least one compoundof claim 44 and at least one pharmaceutically acceptable excipient. 47.A method of treating a subject suffering from or diagnosed with adisease, disorder, or medical condition mediated by P2X7 receptoractivity, comprising administering to a subject in need of suchtreatment an effective amount of at least one compound selected fromcompounds of Formula (I):

and enantiomers or diastereomers thereof; and pharmaceuticallyacceptable salts thereof; wherein: R^(a) is

R¹ is halo or C₁-C₃alkyl; R² is independently selected from the groupconsisting of: H, halo, and C₁-C₃perhaloalkyl; R³ is H or halo; R⁴ ishalo, R⁵ is halo or C₁-C₃perhaloalkyl; R^(b) is independently selectedfrom the group consisting of:

Wherein: R⁶, R⁹, R¹⁰, R¹², R¹⁴ are independently H or halo; R⁷ and R¹³are independently selected from the group consisting of: H, halo andOC₁-C₃alkyl; R⁸ is independently selected from the group consisting of:H, halo, OH and OC₁-C₃alkyl; R¹¹ is independently selected from thegroup consisting of: H, halo and C₁-C₃perhaloalkyl; R^(c) is selectedfrom the group consisting of:

R^(d) and R^(e) are independently H or C₁-C₃alkyl; and provided that atleast one of R^(c), R^(d) and R^(e) are not H.
 48. A method according toclaim 47, wherein the disease, disorder, or medical condition isselected from the group consisting of: diseases of the autoimmune andinflammatory system; diseases of the nervous and neuro-immune system;diseases involved with, and without, neuroinflammation of the CentralNervous System (CNS); diseases of the cardiovascular, metabolic,gastrointestinal and urogenital systems; skeletal disorders, diseasesinvolving the secretory function of exocrine glands and glaucoma,Glomerulonephritis, Chaga's Disease, chlamydia, neuroblastoma,Tuberculosis, Polycystic Kidney Disease, cancer, and acne.
 49. A methodaccording to claim 47 wherein the disease, disorder, or medicalcondition is selected from the group consisting of: rheumatoidarthritis, osteoarthritis, interstitial cystitis, psoriasis, septicshock, sepsis, allergic dermatitis, asthma, allergic asthma, mild tosevere asthma, and steroid resistant asthma, idiopathic pulmonaryfibrosis, allergic rhinitis, chronic obstructive pulmonary disease andairway hyper-responsivenes; acute and chronic pain,neuropathic pain,inflammatory pain, migraine, spontaneous pain, opioid induced pain,diabetic neuropathy, postherpetic neuralgia, low back pain,chemotherapy-induced neuropathic pain, fibromyalgia; mood disorders,major depression, major depressive disorder, treatment resistantdepression, bipolar disorder, anxious depression, anxiety, cognition,sleep disorders, multiple sclerosis, epileptic seizures, Parkinson'sdisease, schizophrenia, Alzheimer's disease, Huntington's disease,Amyotrophic Lateral Sclerosis, autism, spinal cord injury and cerebralischemia/traumatic brain injury, and stress-related disorders; diabetes,diabetes mellitus, thrombosis, irritable bowel disease, irritable bowelsyndrome, Crohn's disease, cardiovascular diseases (examples ofcardiovascular disease include hypertension, myocardial infarction,ischemic heart disease, ischemia, ureteric obstruction, lower urinarytract syndrome, lower urinary tract dysfunction such as incontinence,and disease after cardiac transplantation, osteoporosis/osteopetrosis,diseases involving the secretory function of exocrine glands, glaucoma,Glomerulonephritis, Chaga's Disease, chlamydia, neuroblastoma,Tuberculosis, Polycystic Kidney Disease, cancer, and acne.
 50. A methodaccording to claim 48, wherein the disease, disorder, or medicalcondition is diseases of the autoimmune and inflammatory system.
 51. Amethod according to claim 50, wherein the diseases of the autoimmune andinflammatory system selected from the group consisting of rheumatoidarthritis, osteoarthritis, interstitial cystitis, psoriasis, septicshock, sepsis, allergic dermatitis, asthma, idiopathic pulmonaryfibrosis, allergic rhinitis, chronic obstructive pulmonary disease andairway hyper-responsivenes
 52. The method of claim 48, wherein thedisease, disorder or medical condition is a disease involved with, andwithout, neuroinflammation of the Central Nervous System (CNS).
 53. Amethod according to claim 52, wherein the diseases involved with, andwithout, neuroinflammation of the Central Nervous System (CNS) isselected from the group consisting of: mood disorders, cognition, sleepdisorders, multiple sclerosis, epileptic seizures, Parkinson's disease,schizophrenia, Alzheimer's disease, Huntington's disease, AmyotrophicLateral Sclerosis, autism, spinal cord injury and cerebralischemia/traumatic brain injury, and stress-related disorders
 54. Themethod of claim 53, wherein wherein the mood disorder selected from thegroup consisting of: major depression, major depressive disorder,treatment resistant depression, bipolar disorder, anxious depression,and anxiety.
 55. The method of claim 54, wherein wherein the mooddisorder is treatment resistant depression.